range_common.h

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// SPDX-License-Identifier: 0BSD
 
//
//  Authors:    Igor Pavlov
//              Lasse Collin
//
 
#ifndef LZMA_RANGE_COMMON_H
#define LZMA_RANGE_COMMON_H
 
// Skip common.h if building price_tablegen.c.
#ifndef BUILDING_PRICE_TABLEGEN
#   include "common.h"
#endif
 
 
// Constants //
 
#define RC_SHIFT_BITS 8
#define RC_TOP_BITS 24
#define RC_TOP_VALUE (UINT32_C(1) << RC_TOP_BITS)
#define RC_BIT_MODEL_TOTAL_BITS 11
#define RC_BIT_MODEL_TOTAL (UINT32_C(1) << RC_BIT_MODEL_TOTAL_BITS)
#define RC_MOVE_BITS 5
 
 
// Macros //
 
// Resets the probability so that both 0 and 1 have probability of 50 %
#define bit_reset(prob) \
    prob = RC_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 //
 
typedef uint16_t probability;
 
#endif