85 lines
2.5 KiB
C++
85 lines
2.5 KiB
C++
// Copyright 2009-2020 Intel Corporation
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include "parallel_sort.h"
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namespace embree
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{
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/*! implementation of a key/value map with parallel construction */
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template<typename Key, typename Val>
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class parallel_map
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{
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/* key/value pair to build the map */
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struct KeyValue
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{
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__forceinline KeyValue () {}
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__forceinline KeyValue (const Key key, const Val val)
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: key(key), val(val) {}
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__forceinline operator Key() const {
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return key;
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}
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public:
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Key key;
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Val val;
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};
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public:
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/*! parallel map constructors */
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parallel_map () {}
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/*! construction from pair of vectors */
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template<typename KeyVector, typename ValVector>
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parallel_map (const KeyVector& keys, const ValVector& values) { init(keys,values); }
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/*! initialized the parallel map from a vector with keys and values */
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template<typename KeyVector, typename ValVector>
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void init(const KeyVector& keys, const ValVector& values)
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{
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/* reserve sufficient space for all data */
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assert(keys.size() == values.size());
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vec.resize(keys.size());
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/* generate key/value pairs */
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parallel_for( size_t(0), keys.size(), size_t(4*4096), [&](const range<size_t>& r) {
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for (size_t i=r.begin(); i<r.end(); i++)
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vec[i] = KeyValue((Key)keys[i],values[i]);
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});
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/* perform parallel radix sort of the key/value pairs */
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std::vector<KeyValue> temp(keys.size());
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radix_sort<KeyValue,Key>(vec.data(),temp.data(),keys.size());
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}
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/*! Returns a pointer to the value associated with the specified key. The pointer will be nullptr of the key is not contained in the map. */
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__forceinline const Val* lookup(const Key& key) const
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{
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typename std::vector<KeyValue>::const_iterator i = std::lower_bound(vec.begin(), vec.end(), key);
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if (i == vec.end()) return nullptr;
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if (i->key != key) return nullptr;
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return &i->val;
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}
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/*! If the key is in the map, the function returns the value associated with the key, otherwise it returns the default value. */
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__forceinline Val lookup(const Key& key, const Val& def) const
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{
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typename std::vector<KeyValue>::const_iterator i = std::lower_bound(vec.begin(), vec.end(), key);
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if (i == vec.end()) return def;
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if (i->key != key) return def;
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return i->val;
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}
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/*! clears all state */
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void clear() {
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vec.clear();
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}
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private:
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std::vector<KeyValue> vec; //!< vector containing sorted elements
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};
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}
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