root/src/liblzma/rangecoder/price_tablegen.c

DEFINITIONS

1. init_price_table
2. print_price_table
3. main

///////////////////////////////////////////////////////////////////////////////
//
/// \file       price_tablegen.c
/// \brief      Probability price table generator
///
/// Compiling: gcc -std=c99 -o price_tablegen price_tablegen.c
///
//  Authors:    Igor Pavlov
//              Lasse Collin
//
//  This file has been put into the public domain.
//  You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////

#include <inttypes.h>
#include <stdio.h>
#include "range_common.h"
#include "price.h"


static uint32_t rc_prices[RC_PRICE_TABLE_SIZE];


static void
init_price_table(void)
{
        for (uint32_t i = (UINT32_C(1) << RC_MOVE_REDUCING_BITS) / 2;
                        i < RC_BIT_MODEL_TOTAL;
                        i += (UINT32_C(1) << RC_MOVE_REDUCING_BITS)) {
                const uint32_t cycles_bits = RC_BIT_PRICE_SHIFT_BITS;
                uint32_t w = i;
                uint32_t bit_count = 0;

                for (uint32_t j = 0; j < cycles_bits; ++j) {
                        w *= w;
                        bit_count <<= 1;

                        while (w >= (UINT32_C(1) << 16)) {
                                w >>= 1;
                                ++bit_count;
                        }
                }

                rc_prices[i >> RC_MOVE_REDUCING_BITS]
                                = (RC_BIT_MODEL_TOTAL_BITS << cycles_bits)
                                - 15 - bit_count;
        }

        return;
}


static void
print_price_table(void)
{
        printf("/* This file has been automatically generated by "
                        "price_tablegen.c. */\n\n"
                        "#include \"range_encoder.h\"\n\n"
                        "const uint8_t lzma_rc_prices["
                        "RC_PRICE_TABLE_SIZE] = {");

        const size_t array_size = sizeof(lzma_rc_prices)
                        / sizeof(lzma_rc_prices[0]);
        for (size_t i = 0; i < array_size; ++i) {
                if (i % 8 == 0)
                        printf("\n\t");

                printf("%4" PRIu32, rc_prices[i]);

                if (i != array_size - 1)
                        printf(",");
        }

        printf("\n};\n");

        return;
}


int
main(void)
{
        init_price_table();
        print_price_table();
        return 0;
}