src/liblzma/rangecoder/price_tablegen.c

   1 // SPDX-License-Identifier: 0BSD
   2
   3 ///////////////////////////////////////////////////////////////////////////////
   4 //
   5 /// \file       price_tablegen.c
   6 /// \brief      Probability price table generator
   7 ///
   8 /// Compiling: gcc -std=c99 -o price_tablegen price_tablegen.c
   9 ///
  10 //  Authors:    Igor Pavlov
  11 //              Lasse Collin
  12 //
  13 ///////////////////////////////////////////////////////////////////////////////
  14
  15 #include <inttypes.h>
  16 #include <stdio.h>
  17
  18 // Make it compile without common.h.
  19 #define BUILDING_PRICE_TABLEGEN
  20 #define lzma_attr_visibility_hidden
  21
  22 #include "range_common.h"
  23 #include "price.h"
  24
  25
  26 static uint32_t rc_prices[RC_PRICE_TABLE_SIZE];
  27
  28
  29 static void
  30 init_price_table(void)
  31 {
  32         for (uint32_t i = (UINT32_C(1) << RC_MOVE_REDUCING_BITS) / 2;
  33                         i < RC_BIT_MODEL_TOTAL;
  34                         i += (UINT32_C(1) << RC_MOVE_REDUCING_BITS)) {
  35                 const uint32_t cycles_bits = RC_BIT_PRICE_SHIFT_BITS;
  36                 uint32_t w = i;
  37                 uint32_t bit_count = 0;
  38
  39                 for (uint32_t j = 0; j < cycles_bits; ++j) {
  40                         w *= w;
  41                         bit_count <<= 1;
  42
  43                         while (w >= (UINT32_C(1) << 16)) {
  44                                 w >>= 1;
  45                                 ++bit_count;
  46                         }
  47                 }
  48
  49                 rc_prices[i >> RC_MOVE_REDUCING_BITS]
  50                                 = (RC_BIT_MODEL_TOTAL_BITS << cycles_bits)
  51                                 - 15 - bit_count;
  52         }
  53
  54         return;
  55 }
  56
  57
  58 static void
  59 print_price_table(void)
  60 {
  61         // Split the SPDX string so that it won't accidentally match
  62         // when tools search for the string.
  63         printf("// SPDX" "-License-Identifier" ": 0BSD\n\n"
  64                 "// This file has been generated by price_tablegen.c.\n\n"
  65                 "#include \"range_encoder.h\"\n\n"
  66                 "const uint8_t lzma_rc_prices["
  67                 "RC_PRICE_TABLE_SIZE] = {");
  68
  69         const size_t array_size = sizeof(lzma_rc_prices)
  70                         / sizeof(lzma_rc_prices[0]);
  71         for (size_t i = 0; i < array_size; ++i) {
  72                 if (i % 8 == 0)
  73                         printf("\n\t");
  74
  75                 printf("%4" PRIu32, rc_prices[i]);
  76
  77                 if (i != array_size - 1)
  78                         printf(",");
  79         }
  80
  81         printf("\n};\n");
  82
  83         return;
  84 }
  85
  86
  87 int
  88 main(void)
  89 {
  90         init_price_table();
  91         print_price_table();
  92         return 0;
  93 }