The R Project SVN R

///////////////////////////////////////////////////////////////////////////////
//
/// \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;
}