#include "transpositiontable.h"
#include "constants.h"
#include <ctime>
namespace Napoleon
{
TranspositionTable::TranspositionTable(unsigned long size)
{
BucketSize = 4;
Size = size/(sizeof(HashEntry*)*BucketSize);
Table = new HashEntry*[Size];
for (unsigned i=0; i<Size; i++)
{
Table[i] = new HashEntry[BucketSize];
}
}
void TranspositionTable::Save(ZobristKey key, Byte depth, int score, Move move, Byte bound)
{
HashEntry* hash;
int min = Constants::MaxPly;
for (int i=0; i<BucketSize; i++)
{
hash = &Table[key % Size][i];
if (hash->Depth < min)
min = hash->Depth;
}
hash = &Table[key % Size][min];
hash->Hash = key;
hash->Score = score;
hash->Depth = depth;
hash->Bound = bound;
hash->BestMove = move;
}
int TranspositionTable::Probe(ZobristKey key, Byte depth, int alpha, Move* move, int beta)
{
HashEntry* hash = &Table[key % Size][0];
for (int i=0; i<BucketSize; i++, hash++)
{
if (hash->Hash == key)
{
if (hash->Depth >= depth)
{
if (hash->Bound == Exact)
return hash->Score;
if (hash->Bound == Alpha && hash->Score <= alpha)
return alpha;
if (hash->Bound == Beta && hash->Score >= beta)
return beta;
}
*move = hash->BestMove; // get best move on this position
}
}
return TranspositionTable::Unknown;
}
void TranspositionTable::Clear()
{
for (unsigned i=0 ; i<Size; i++)
{
for (int l=0; l<BucketSize; l++)
Table[i][l].Hash = 0;
}
}
Move TranspositionTable::GetPv(ZobristKey key)
{
HashEntry* hash = &Table[key % Size][0];
for (int i=0; i<BucketSize; i++, hash++)
{
if (hash->Hash == key)
{
if (!hash->BestMove.IsNull())
return hash->BestMove;
}
}
return Constants::NullMove;
}
}
