src/liblzma/rangecoder/price_tablegen.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       price_tablegen.c
   4 /// \brief      Probability price table generator
   5 ///
   6 /// Compiling: gcc -std=c99 -o price_tablegen price_tablegen.c
   7 ///
   8 //  Authors:    Igor Pavlov
   9 //              Lasse Collin
  10 //
  11 //  This file has been put into the public domain.
  12 //  You can do whatever you want with this file.
  13 //
  14 ///////////////////////////////////////////////////////////////////////////////
  15
  16 #include <inttypes.h>
  17 #include <stdio.h>
  18 #include "range_common.h"
  19 #include "price.h"
  20
  21
  22 static uint32_t rc_prices[RC_PRICE_TABLE_SIZE];
  23
  24
  25 static void
  26 init_price_table(void)
  27 {
  28         for (uint32_t i = (UINT32_C(1) << RC_MOVE_REDUCING_BITS) / 2;
  29                         i < RC_BIT_MODEL_TOTAL;
  30                         i += (UINT32_C(1) << RC_MOVE_REDUCING_BITS)) {
  31                 const uint32_t cycles_bits = RC_BIT_PRICE_SHIFT_BITS;
  32                 uint32_t w = i;
  33                 uint32_t bit_count = 0;
  34
  35                 for (uint32_t j = 0; j < cycles_bits; ++j) {
  36                         w *= w;
  37                         bit_count <<= 1;
  38
  39                         while (w >= (UINT32_C(1) << 16)) {
  40                                 w >>= 1;
  41                                 ++bit_count;
  42                         }
  43                 }
  44
  45                 rc_prices[i >> RC_MOVE_REDUCING_BITS]
  46                                 = (RC_BIT_MODEL_TOTAL_BITS << cycles_bits)
  47                                 - 15 - bit_count;
  48         }
  49
  50         return;
  51 }
  52
  53
  54 static void
  55 print_price_table(void)
  56 {
  57         printf("/* This file has been automatically generated by "
  58                         "price_tablegen.c. */\n\n"
  59                         "#include \"range_encoder.h\"\n\n"
  60                         "const uint8_t lzma_rc_prices["
  61                         "RC_PRICE_TABLE_SIZE] = {");
  62
  63         const size_t array_size = sizeof(lzma_rc_prices)
  64                         / sizeof(lzma_rc_prices[0]);
  65         for (size_t i = 0; i < array_size; ++i) {
  66                 if (i % 8 == 0)
  67                         printf("\n\t");
  68
  69                 printf("%4" PRIu32, rc_prices[i]);
  70
  71                 if (i != array_size - 1)
  72                         printf(",");
  73         }
  74
  75         printf("\n};\n");
  76
  77         return;
  78 }
  79
  80
  81 int
  82 main(void)
  83 {
  84         init_price_table();
  85         print_price_table();
  86         return 0;
  87 }