BaseTools/Source/C/BrotliCompress/enc/cluster.c

   1 /* Copyright 2013 Google Inc. All Rights Reserved.
   2
   3    Distributed under MIT license.
   4    See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
   5 */
   6
   7 /* Functions for clustering similar histograms together. */
   8
   9 #include "./cluster.h"
  10
  11 #include "../common/types.h"
  12 #include "./bit_cost.h"  /* BrotliPopulationCost */
  13 #include "./fast_log.h"
  14 #include "./histogram.h"
  15 #include "./memory.h"
  16 #include "./port.h"
  17
  18 #if defined(__cplusplus) || defined(c_plusplus)
  19 extern "C" {
  20 #endif
  21
  22 static BROTLI_INLINE BROTLI_BOOL HistogramPairIsLess(
  23     const HistogramPair* p1, const HistogramPair* p2) {
  24   if (p1->cost_diff != p2->cost_diff) {
  25     return TO_BROTLI_BOOL(p1->cost_diff > p2->cost_diff);
  26   }
  27   return TO_BROTLI_BOOL((p1->idx2 - p1->idx1) > (p2->idx2 - p2->idx1));
  28 }
  29
  30 /* Returns entropy reduction of the context map when we combine two clusters. */
  31 static BROTLI_INLINE double ClusterCostDiff(size_t size_a, size_t size_b) {
  32   size_t size_c = size_a + size_b;
  33   return (double)size_a * FastLog2(size_a) +
  34     (double)size_b * FastLog2(size_b) -
  35     (double)size_c * FastLog2(size_c);
  36 }
  37
  38 #define CODE(X) X
  39
  40 #define FN(X) X ## Literal
  41 #include "./cluster_inc.h"  /* NOLINT(build/include) */
  42 #undef FN
  43
  44 #define FN(X) X ## Command
  45 #include "./cluster_inc.h"  /* NOLINT(build/include) */
  46 #undef FN
  47
  48 #define FN(X) X ## Distance
  49 #include "./cluster_inc.h"  /* NOLINT(build/include) */
  50 #undef FN
  51
  52 #undef CODE
  53
  54 #if defined(__cplusplus) || defined(c_plusplus)
  55 }  /* extern "C" */
  56 #endif