source: vbox/trunk/src/libs/liblzma-5.8.1/lzma/fastpos_tablegen.c@ 108911

// SPDX-License-Identifier: 0BSD

///////////////////////////////////////////////////////////////////////////////
//
/// \file       fastpos_tablegen.c
/// \brief      Generates the lzma_fastpos[] lookup table
///
//  Authors:    Igor Pavlov
//              Lasse Collin
//
///////////////////////////////////////////////////////////////////////////////

#include <inttypes.h>
#include <stdio.h>

#define lzma_attr_visibility_hidden
#include "fastpos.h"


int
main(void)
{
        uint8_t fastpos[1 << FASTPOS_BITS];

        const uint8_t fast_slots = 2 * FASTPOS_BITS;
        uint32_t c = 2;

        fastpos[0] = 0;
        fastpos[1] = 1;

        for (uint8_t slot_fast = 2; slot_fast < fast_slots; ++slot_fast) {
                const uint32_t k = 1 << ((slot_fast >> 1) - 1);
                for (uint32_t j = 0; j < k; ++j, ++c)
                        fastpos[c] = slot_fast;
        }

        // Split the SPDX string so that it won't accidentally match
        // when tools search for the string.
        printf("// SPDX" "-License-Identifier" ": 0BSD\n\n"
                "// This file has been generated by fastpos_tablegen.c.\n\n"
                "#include \"common.h\"\n"
                "#include \"fastpos.h\"\n\n"
                "const uint8_t lzma_fastpos[1 << FASTPOS_BITS] = {");

        for (size_t i = 0; i < (1 << FASTPOS_BITS); ++i) {
                if (i % 16 == 0)
                        printf("\n\t");

                printf("%3u", (unsigned int)(fastpos[i]));

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

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

        return 0;
}