Files
MinecraftConsoles/Minecraft.World/JavaIntHash.h
2026-03-01 12:16:08 +08:00

78 lines
2.0 KiB
C

#pragma once
// Java doesn't have a default hash value for ints, however, the hashmap itself does some "supplemental" hashing, so
// our ints actually get hashed by code as implemented below. std templates *do* have a standard hash for ints, but it
// would appear to be a bit expensive so matching the java one for now anyway. This code implements the supplemental
// hashing that happens in java so we can match what their maps are doing with ints.
typedef struct
{
int operator() (const int &k) const
{
int h = k;
h += ~(h << 9);
h ^= (((unsigned int)h) >> 14);
h += (h << 4);
h ^= (((unsigned int)h) >> 10);
return h;
}
} IntKeyHash;
typedef struct
{
bool operator() (const int &x, const int &y) const { return x==y; }
} IntKeyEq;
// This hash functor is taken from the IntHashMap java class used by the game, so that we can use a standard std hashmap with this hash rather
// than implement the class itself
typedef struct
{
int operator() (const int &k) const
{
unsigned int h = (unsigned int)k;
h ^= (h >> 20) ^ (h >> 12);
return (int)(h ^ (h >> 7) ^ (h >> 4));
}
} IntKeyHash2;
// This hash functor is taken from the LongHashMap java class used by the game, so that we can use a standard std hashmap with this hash rather
// than implement the class itself
typedef struct
{
int hash(const int &k) const
{
unsigned int h = (unsigned int)k;
h ^= (h >> 20) ^ (h >> 12);
return (int)(h ^ (h >> 7) ^ (h >> 4));
}
int operator() (const __int64 &k) const
{
return hash((int) ( k ^ (((__uint64)k) >> 32 )));
}
} LongKeyHash;
typedef struct
{
bool operator() (const __int64 &x, const __int64 &y) const { return x==y; }
} LongKeyEq;
typedef struct
{
int operator() (const eINSTANCEOF &k) const
{
unsigned int h = (unsigned int)k;
h ^= (h >> 20) ^ (h >> 12);
return (int)(h ^ (h >> 7) ^ (h >> 4));
}
} eINSTANCEOFKeyHash;
typedef struct
{
bool operator() (const eINSTANCEOF &x, const eINSTANCEOF &y) const { return x==y; }
} eINSTANCEOFKeyEq;