/* 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 int HistogramPairIsLess(
const HistogramPair* p1, const HistogramPair* p2) {
if (p1->cost_diff != p2->cost_diff) {
return (p1->cost_diff > p2->cost_diff) ? 1 : 0;
}
return ((p1->idx2 - p1->idx1) > (p2->idx2 - p2->idx1)) ? 1 : 0;
}
/* 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
