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DEFINITIONS
This source file includes following definitions.
- hash_init
- hash_key
- hash_pawn_key
- hash_material_key
- hash_piece_key
- hash_castle_key
- hash_ep_key
- hash_turn_key
- hash_counter_key
// hash.cpp
// includes
#include "board.h"
#include "hash.h"
#include "piece.h"
#include "random.h"
#include "square.h"
#include "util.h"
// variables
uint64 Castle64[16];
// prototypes
static uint64 hash_counter_key (int piece_12, int count);
// functions
// hash_init()
void hash_init() {
int i;
for (i = 0; i < 16; i++) Castle64[i] = hash_castle_key(i);
}
// hash_key()
uint64 hash_key(const board_t * board) {
uint64 key;
int colour;
const sq_t * ptr;
int sq, piece;
ASSERT(board!=NULL);
// init
key = 0;
// pieces
for (colour = 0; colour < ColourNb; colour++) {
for (ptr = &board->piece[colour][0]; (sq=*ptr) != SquareNone; ptr++) {
piece = board->square[sq];
key ^= hash_piece_key(piece,sq);
}
for (ptr = &board->pawn[colour][0]; (sq=*ptr) != SquareNone; ptr++) {
piece = board->square[sq];
key ^= hash_piece_key(piece,sq);
}
}
// castle flags
key ^= hash_castle_key(board->flags);
// en-passant square
sq = board->ep_square;
if (sq != SquareNone) key ^= hash_ep_key(sq);
// turn
key ^= hash_turn_key(board->turn);
return key;
}
// hash_pawn_key()
uint64 hash_pawn_key(const board_t * board) {
uint64 key;
int colour;
const sq_t * ptr;
int sq, piece;
ASSERT(board!=NULL);
// init
key = 0;
// pawns
for (colour = 0; colour < ColourNb; colour++) {
for (ptr = &board->pawn[colour][0]; (sq=*ptr) != SquareNone; ptr++) {
piece = board->square[sq];
key ^= hash_piece_key(piece,sq);
}
}
return key;
}
// hash_material_key()
uint64 hash_material_key(const board_t * board) {
uint64 key;
int piece_12, count;
ASSERT(board!=NULL);
// init
key = 0;
// counters
for (piece_12 = 0; piece_12 < 12; piece_12++) {
count = board->number[piece_12];
key ^= hash_counter_key(piece_12,count);
}
return key;
}
// hash_piece_key()
uint64 hash_piece_key(int piece, int square) {
ASSERT(piece_is_ok(piece));
ASSERT(SQUARE_IS_OK(square));
return RANDOM_64(RandomPiece+(PIECE_TO_12(piece)^1)*64+SQUARE_TO_64(square)); // HACK: ^1 for PolyGlot book
}
// hash_castle_key()
uint64 hash_castle_key(int flags) {
uint64 key;
int i;
ASSERT((flags&~0xF)==0);
key = 0;
for (i = 0; i < 4; i++) {
if ((flags & (1<<i)) != 0) key ^= RANDOM_64(RandomCastle+i);
}
return key;
}
// hash_ep_key()
uint64 hash_ep_key(int square) {
ASSERT(SQUARE_IS_OK(square));
return RANDOM_64(RandomEnPassant+SQUARE_FILE(square)-FileA);
}
// hash_turn_key()
uint64 hash_turn_key(int colour) {
ASSERT(COLOUR_IS_OK(colour));
return (COLOUR_IS_WHITE(colour)) ? RANDOM_64(RandomTurn) : 0;
}
// hash_counter_key()
static uint64 hash_counter_key(int piece_12, int count) {
uint64 key;
int i, index;
ASSERT(piece_12>=0&&piece_12<12);
ASSERT(count>=0&&count<=10);
// init
key = 0;
// counter
index = piece_12 * 16;
for (i = 0; i < count; i++) key ^= RANDOM_64(index+i);
return key;
}
// end of hash.cpp