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84 lines
2.0 KiB
C++
84 lines
2.0 KiB
C++
// This code is in the public domain -- Ignacio Castaño <castano@gmail.com>
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#pragma once
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#ifndef NV_CORE_HASH_H
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#define NV_CORE_HASH_H
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#include "nvcore.h"
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namespace nv
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{
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inline uint sdbmHash(const void * data_in, uint size, uint h = 5381)
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{
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const uint8 * data = (const uint8 *) data_in;
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uint i = 0;
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while (i < size) {
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h = (h << 16) + (h << 6) - h + (uint) data[i++];
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}
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return h;
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}
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// Note that this hash does not handle NaN properly.
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inline uint sdbmFloatHash(const float * f, uint count, uint h = 5381)
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{
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for (uint i = 0; i < count; i++) {
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//nvDebugCheck(nv::isFinite(*f));
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union { float f; uint32 i; } x = { f[i] };
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if (x.i == 0x80000000) x.i = 0;
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h = sdbmHash(&x, 4, h);
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}
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return h;
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}
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template <typename T>
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inline uint hash(const T & t, uint h = 5381)
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{
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return sdbmHash(&t, sizeof(T), h);
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}
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template <>
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inline uint hash(const float & f, uint h)
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{
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return sdbmFloatHash(&f, 1, h);
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}
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// Functors for hash table:
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template <typename Key> struct Hash
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{
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uint operator()(const Key & k) const {
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return hash(k);
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}
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};
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template <typename Key> struct Equal
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{
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bool operator()(const Key & k0, const Key & k1) const {
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return k0 == k1;
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}
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};
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// @@ Move to Utils.h?
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template <typename T1, typename T2>
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struct Pair {
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T1 first;
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T2 second;
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};
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template <typename T1, typename T2>
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bool operator==(const Pair<T1,T2> & p0, const Pair<T1,T2> & p1) {
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return p0.first == p1.first && p0.second == p1.second;
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}
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template <typename T1, typename T2>
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uint hash(const Pair<T1,T2> & p, uint h = 5381) {
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return hash(p.second, hash(p.first));
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}
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} // nv namespace
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#endif // NV_CORE_HASH_H
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