diff options
Diffstat (limited to '')
-rw-r--r-- | third_party/jpeg-xl/lib/jxl/enc_cluster.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/enc_cluster.h b/third_party/jpeg-xl/lib/jxl/enc_cluster.h new file mode 100644 index 0000000000..4b062e820c --- /dev/null +++ b/third_party/jpeg-xl/lib/jxl/enc_cluster.h @@ -0,0 +1,63 @@ +// Copyright (c) the JPEG XL Project Authors. All rights reserved. +// +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Functions for clustering similar histograms together. + +#ifndef LIB_JXL_ENC_CLUSTER_H_ +#define LIB_JXL_ENC_CLUSTER_H_ + +#include <stddef.h> +#include <stdint.h> +#include <string.h> + +#include <vector> + +#include "lib/jxl/ans_params.h" +#include "lib/jxl/enc_ans.h" + +namespace jxl { + +struct Histogram { + Histogram() { + total_count_ = 0; + entropy_ = 0.0; + } + void Clear() { + data_.clear(); + total_count_ = 0; + } + void Add(size_t symbol) { + if (data_.size() <= symbol) { + data_.resize(DivCeil(symbol + 1, kRounding) * kRounding); + } + ++data_[symbol]; + ++total_count_; + } + void AddHistogram(const Histogram& other) { + if (other.data_.size() > data_.size()) { + data_.resize(other.data_.size()); + } + for (size_t i = 0; i < other.data_.size(); ++i) { + data_[i] += other.data_[i]; + } + total_count_ += other.total_count_; + } + float PopulationCost() const { + return ANSPopulationCost(data_.data(), data_.size()); + } + float ShannonEntropy() const; + + std::vector<ANSHistBin> data_; + size_t total_count_; + mutable float entropy_; // WARNING: not kept up-to-date. + static constexpr size_t kRounding = 8; +}; + +void ClusterHistograms(HistogramParams params, const std::vector<Histogram>& in, + size_t max_histograms, std::vector<Histogram>* out, + std::vector<uint32_t>* histogram_symbols); +} // namespace jxl + +#endif // LIB_JXL_ENC_CLUSTER_H_ |