/* lzo1a_de.h -- definitions for the the LZO1A algorithm
This file is part of the LZO real-time data compression library.
Copyright (C) 1996-2014 Markus Franz Xaver Johannes Oberhumer
All Rights Reserved.
The LZO library 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 (at your option) any later version.
The LZO library 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 the LZO library; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Markus F.X.J. Oberhumer
<markus@oberhumer.com>
http://www.oberhumer.com/opensource/lzo/
*/
/* WARNING: this file should *not* be used by applications. It is
part of the implementation of the LZO package and is subject
to change.
*/
#ifndef __LZO_DEFS_H
#define __LZO_DEFS_H 1
#ifdef __cplusplus
extern "C" {
#endif
/***********************************************************************
//
************************************************************************/
/*
Format of the marker byte
76543210
--------
00000000 a long literal run ('R0' run) - there are short and long R0 runs
000rrrrr a short literal run with len r
mmmooooo a short match (len = 2+m, o = offset low bits)
111ooooo a long match (o = offset low bits)
*/
#define RSIZE (1 << RBITS)
#define RMASK (RSIZE - 1)
#define MBITS (8 - OBITS)
#define MSIZE (1 << MBITS)
#define MMASK (MSIZE - 1)
#define OBITS RBITS /* offset and run-length use same bits */
#define OSIZE (1 << OBITS)
#define OMASK (OSIZE - 1)
/* additional bits for coding the length in a long match */
#define LBITS 8
#define LSIZE (1 << LBITS)
#define LMASK (LSIZE - 1)
/***********************************************************************
// some macros to improve readability
************************************************************************/
/* Minimum len of a match */
#define MIN_MATCH 3
#define THRESHOLD (MIN_MATCH - 1)
/* Min-/Maximum len of a match coded in 2 bytes */
#define MIN_MATCH_SHORT (MIN_MATCH)
#define MAX_MATCH_SHORT (MIN_MATCH_SHORT + (MSIZE - 2) - 1)
/* why (MSIZE - 2) ? because 0 is used to mark runs,
* and MSIZE-1 is used to mark a long match */
/* Min-/Maximum len of a match coded in 3 bytes */
#define MIN_MATCH_LONG (MAX_MATCH_SHORT + 1)
#define MAX_MATCH_LONG (MIN_MATCH_LONG + LSIZE - 1)
/* Min-/Maximum offset of a match */
#define MIN_OFFSET 1
#define MAX_OFFSET (1 << (CHAR_BIT + OBITS))
/* R0 literal run (a long run) */
#define R0MIN (RSIZE) /* Minimum len of R0 run of literals */
#define R0MAX (R0MIN + 255) /* Maximum len of R0 run of literals */
#define R0FAST (R0MAX & ~7) /* R0MAX aligned to 8 byte boundary */
#if (R0MAX - R0FAST != 7) || ((R0FAST & 7) != 0)
# error "something went wrong"
#endif
/* 7 special codes from R0FAST+1 .. R0MAX
* these codes mean long R0 runs with lengths
* 512, 1024, 2048, 4096, 8192, 16384, 32768 */
/*
RBITS | MBITS MIN THR. MSIZE MAXS MINL MAXL MAXO R0MAX R0FAST
======+===============================================================
3 | 5 3 2 32 32 33 288 2048 263 256
4 | 4 3 2 16 16 17 272 4096 271 264
5 | 3 3 2 8 8 9 264 8192 287 280
*/
/***********************************************************************
//
************************************************************************/
#define DBITS 13
#include "lzo_dict.h"
#define DVAL_LEN DVAL_LOOKAHEAD
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* already included */
/*
vi:ts=4:et
*/