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