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igl/external/embree/kernels/algorithms/pmap.h
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// ======================================================================== //
// Copyright 2009-2014 Intel Corporation //
// //
// Licensed under the Apache License, Version 2.0 (the "License"); //
// you may not use this file except in compliance with the License. //
// You may obtain a copy of the License at //
// //
// http://www.apache.org/licenses/LICENSE-2.0 //
// //
// Unless required by applicable law or agreed to in writing, software //
// distributed under the License is distributed on an "AS IS" BASIS, //
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. //
// See the License for the specific language governing permissions and //
// limitations under the License. //
// ======================================================================== //
#pragma once
#include "common/default.h"
#include "common/buffer.h"
#include "algorithms/sort.h"
#include "algorithms/parallel_for.h"
namespace embree
{
/*! implementation of a map key/value map with parallel construction */
template<typename Key, typename Val>
class pmap
{
struct KeyValue
{
__forceinline KeyValue () {}
__forceinline KeyValue (const Key key, const Val val)
: key(key), val(val) {}
__forceinline operator Key() const {
return key;
}
public:
Key key;
Val val;
};
public:
/*! parallel map constructors */
pmap () {}
template<typename SourceKey>
pmap (const std::vector<SourceKey>& keys, const std::vector<Val>& values) { init(keys,values); }
template<typename SourceKey>
pmap (const BufferT<SourceKey>& keys, const BufferT<Val>& values) { init(keys,values); }
/*! initialized the parallel map from a vector with keys and values */
template<typename SourceKey>
void init(const std::vector<SourceKey>& keys, const std::vector<Val>& values)
{
/* reserve sufficient space for all data */
assert(keys.size() == values.size());
vec.resize(keys.size());
temp.resize(keys.size());
/* generate key/value pairs */
parallel_for( size_t(0), keys.size(), size_t(4*4096), [&](const range<size_t>& r) {
for (size_t i=r.begin(); i<r.end(); i++)
vec[i] = KeyValue((Key)keys[i],values[i]);
});
/* perform parallel radix sort of the key/value pairs */
radix_sort<KeyValue,Key>(vec.data(),temp.data(),keys.size());
}
/*! initialized the parallel map from user buffers with keys and values */
template<typename SourceKey>
void init(const BufferT<SourceKey>& keys, const BufferT<Val>& values)
{
/* reserve sufficient space for all data */
assert(keys.size() == values.size());
vec.resize(keys.size());
temp.resize(keys.size());
/* generate key/value pairs */
parallel_for( size_t(0), keys.size(), size_t(4*4096), [&](const range<size_t>& r) {
for (size_t i=r.begin(); i<r.end(); i++)
vec[i] = KeyValue((Key)keys[i],values[i]);
});
/* perform parallel radix sort of the key/value pairs */
radix_sort<KeyValue,Key>(vec.data(),temp.data(),keys.size());
}
/*! Returns a pointer to the value associated with the specified key. The pointer will be NULL of the key is not contained in the map. */
__forceinline const Val* lookup(const Key& key) const
{
typename std::vector<KeyValue>::const_iterator i = std::lower_bound(vec.begin(), vec.end(), key);
if (i == vec.end()) return NULL;
if (i->key != key) return NULL;
return &i->val;
}
/*! If the key is in the map, the function returns the value associated with the key, otherwise it returns the default value. */
__forceinline Val lookup(const Key& key, const Val& def) const
{
typename std::vector<KeyValue>::const_iterator i = std::lower_bound(vec.begin(), vec.end(), key);
if (i == vec.end()) return def;
if (i->key != key) return def;
return i->val;
}
/*! cleans temporary state required for re-construction */
void cleanup() {
temp.clear();
}
/*! clears all state */
void clear() {
vec.clear();
temp.clear();
}
private:
std::vector<KeyValue> vec; //!< vector containing sorted elements
std::vector<KeyValue> temp; //!< temporary vector required during construction only
};
}