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///////////////////////////////////////////////////////////////////////////////
//
/// \file range_common.h
/// \brief Common things for range encoder and decoder
//
// Copyright (C) 1999-2006 Igor Pavlov
// Copyright (C) 2006 Lasse Collin
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This 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
// Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////
#ifndef LZMA_RANGE_COMMON_H
#define LZMA_RANGE_COMMON_H
#ifdef HAVE_CONFIG_H
# include "common.h"
#endif
///////////////
// Constants //
///////////////
#define SHIFT_BITS 8
#define TOP_BITS 24
#define TOP_VALUE (UINT32_C(1) << TOP_BITS)
#define BIT_MODEL_TOTAL_BITS 11
#define BIT_MODEL_TOTAL (UINT32_C(1) << BIT_MODEL_TOTAL_BITS)
#define MOVE_BITS 5
#define MOVE_REDUCING_BITS 2
#define BIT_PRICE_SHIFT_BITS 6
////////////
// Macros //
////////////
// Resets the probability so that both 0 and 1 have probability of 50 %
#define bit_reset(prob) \
prob = BIT_MODEL_TOTAL >> 1
// This does the same for a complete bit tree.
// (A tree represented as an array.)
#define bittree_reset(probs, bit_levels) \
for (uint32_t bt_i = 0; bt_i < (1 << (bit_levels)); ++bt_i) \
bit_reset((probs)[bt_i])
//////////////////////
// Type definitions //
//////////////////////
// Bit coder speed optimization
// uint16_t is enough for probability, but usually uint32_t is faster and it
// doesn't waste too much memory. If uint64_t is fastest on 64-bit CPU, you
// probably want to use that instead of uint32_t. With uint64_t you will
// waste RAM _at maximum_ of 4.5 MiB (same for both encoding and decoding).
typedef uint32_t probability;
#endif
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