/* Copyright 2013 Google Inc. All Rights Reserved. | |
Distributed under MIT license. | |
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT | |
*/ | |
/* Functions for clustering similar histograms together. */ | |
#include "./cluster.h" | |
#include "../common/types.h" | |
#include "./bit_cost.h" /* BrotliPopulationCost */ | |
#include "./fast_log.h" | |
#include "./histogram.h" | |
#include "./memory.h" | |
#include "./port.h" | |
#if defined(__cplusplus) || defined(c_plusplus) | |
extern "C" { | |
#endif | |
static BROTLI_INLINE BROTLI_BOOL HistogramPairIsLess( | |
const HistogramPair* p1, const HistogramPair* p2) { | |
if (p1->cost_diff != p2->cost_diff) { | |
return TO_BROTLI_BOOL(p1->cost_diff > p2->cost_diff); | |
} | |
return TO_BROTLI_BOOL((p1->idx2 - p1->idx1) > (p2->idx2 - p2->idx1)); | |
} | |
/* Returns entropy reduction of the context map when we combine two clusters. */ | |
static BROTLI_INLINE double ClusterCostDiff(size_t size_a, size_t size_b) { | |
size_t size_c = size_a + size_b; | |
return (double)size_a * FastLog2(size_a) + | |
(double)size_b * FastLog2(size_b) - | |
(double)size_c * FastLog2(size_c); | |
} | |
#define CODE(X) X | |
#define FN(X) X ## Literal | |
#include "./cluster_inc.h" /* NOLINT(build/include) */ | |
#undef FN | |
#define FN(X) X ## Command | |
#include "./cluster_inc.h" /* NOLINT(build/include) */ | |
#undef FN | |
#define FN(X) X ## Distance | |
#include "./cluster_inc.h" /* NOLINT(build/include) */ | |
#undef FN | |
#undef CODE | |
#if defined(__cplusplus) || defined(c_plusplus) | |
} /* extern "C" */ | |
#endif |