| 1 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\ |
| 2 | * This is GNU Go, a Go program. Contact gnugo@gnu.org, or see * |
| 3 | * http://www.gnu.org/software/gnugo/ for more information. * |
| 4 | * * |
| 5 | * Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, * |
| 6 | * 2008 and 2009 by the Free Software Foundation. * |
| 7 | * * |
| 8 | * This program is free software; you can redistribute it and/or * |
| 9 | * modify it under the terms of the GNU General Public License as * |
| 10 | * published by the Free Software Foundation - version 3 or * |
| 11 | * (at your option) any later version. * |
| 12 | * * |
| 13 | * This program is distributed in the hope that it will be useful, * |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
| 16 | * GNU General Public License in file COPYING for more details. * |
| 17 | * * |
| 18 | * You should have received a copy of the GNU General Public * |
| 19 | * License along with this program; if not, write to the Free * |
| 20 | * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, * |
| 21 | * Boston, MA 02111, USA. * |
| 22 | \* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 23 | |
| 24 | |
| 25 | #include "board.h" |
| 26 | #include "hash.h" |
| 27 | #include "random.h" |
| 28 | |
| 29 | #include <stdio.h> |
| 30 | #include <stdlib.h> |
| 31 | #include <limits.h> |
| 32 | |
| 33 | |
| 34 | |
| 35 | /* |
| 36 | * This file, together with engine/hash.h implements hashing of go positions |
| 37 | * using a method known as Zobrist hashing. See the Texinfo documentation |
| 38 | * (Reading/Hashing) for more information. |
| 39 | */ |
| 40 | |
| 41 | |
| 42 | /* ================================================================ */ |
| 43 | |
| 44 | |
| 45 | |
| 46 | |
| 47 | /* Random values for the board hash function. For stones and ko position. */ |
| 48 | static Hash_data white_hash[BOARDMAX]; |
| 49 | static Hash_data black_hash[BOARDMAX]; |
| 50 | static Hash_data ko_hash[BOARDMAX]; |
| 51 | static Hash_data komaster_hash[NUM_KOMASTER_STATES]; |
| 52 | static Hash_data kom_pos_hash[BOARDMAX]; |
| 53 | static Hash_data goal_hash[BOARDMAX]; |
| 54 | |
| 55 | |
| 56 | /* Get a random Hashvalue, where all bits are used. */ |
| 57 | static Hashvalue |
| 58 | hash_rand(void) |
| 59 | { |
| 60 | int i; |
| 61 | Hashvalue h = 0; |
| 62 | |
| 63 | for (i = 0; 32*i < (int) (CHAR_BIT*sizeof(Hashvalue)); i++) |
| 64 | h |= (Hashvalue) gg_urand() << 32*i; |
| 65 | |
| 66 | return h; |
| 67 | } |
| 68 | |
| 69 | /* Fill an array with random numbers for Zobrist hashing. */ |
| 70 | void |
| 71 | hash_init_zobrist_array(Hash_data *array, int size) |
| 72 | { |
| 73 | int i, j; |
| 74 | for (i = 0; i < size; i++) |
| 75 | for (j = 0; j < NUM_HASHVALUES; j++) |
| 76 | array[i].hashval[j] = hash_rand(); |
| 77 | } |
| 78 | |
| 79 | /* |
| 80 | * Initialize the board hash system. |
| 81 | */ |
| 82 | |
| 83 | void |
| 84 | hash_init(void) |
| 85 | { |
| 86 | static int is_initialized = 0; |
| 87 | if (is_initialized) |
| 88 | return; |
| 89 | |
| 90 | INIT_ZOBRIST_ARRAY(black_hash); |
| 91 | INIT_ZOBRIST_ARRAY(white_hash); |
| 92 | INIT_ZOBRIST_ARRAY(ko_hash); |
| 93 | INIT_ZOBRIST_ARRAY(komaster_hash); |
| 94 | INIT_ZOBRIST_ARRAY(kom_pos_hash); |
| 95 | INIT_ZOBRIST_ARRAY(goal_hash); |
| 96 | |
| 97 | is_initialized = 1; |
| 98 | } |
| 99 | |
| 100 | |
| 101 | /* ---------------------------------------------------------------- */ |
| 102 | |
| 103 | /* Calculate the hashvalue from scratch. */ |
| 104 | void |
| 105 | hashdata_recalc(Hash_data *hd, Intersection *p, int ko_pos) |
| 106 | { |
| 107 | int pos; |
| 108 | |
| 109 | hashdata_clear(hd); |
| 110 | |
| 111 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 112 | if (p[pos] == WHITE) |
| 113 | hashdata_xor(*hd, white_hash[pos]); |
| 114 | else if (p[pos] == BLACK) |
| 115 | hashdata_xor(*hd, black_hash[pos]); |
| 116 | } |
| 117 | |
| 118 | if (ko_pos != 0) |
| 119 | hashdata_xor(*hd, ko_hash[ko_pos]); |
| 120 | } |
| 121 | |
| 122 | /* Clear hashdata. */ |
| 123 | void |
| 124 | hashdata_clear(Hash_data *hd) |
| 125 | { |
| 126 | int i; |
| 127 | for (i = 0; i < NUM_HASHVALUES; i++) |
| 128 | hd->hashval[i] = 0; |
| 129 | } |
| 130 | |
| 131 | /* Set or remove ko in the hash value and hash position. */ |
| 132 | void |
| 133 | hashdata_invert_ko(Hash_data *hd, int pos) |
| 134 | { |
| 135 | hashdata_xor(*hd, ko_hash[pos]); |
| 136 | } |
| 137 | |
| 138 | |
| 139 | /* Set or remove a stone of COLOR at pos in a Hash_data. */ |
| 140 | void |
| 141 | hashdata_invert_stone(Hash_data *hd, int pos, int color) |
| 142 | { |
| 143 | if (color == BLACK) |
| 144 | hashdata_xor(*hd, black_hash[pos]); |
| 145 | else if (color == WHITE) |
| 146 | hashdata_xor(*hd, white_hash[pos]); |
| 147 | } |
| 148 | |
| 149 | |
| 150 | /* Set or remove the komaster value in the hash data. */ |
| 151 | void |
| 152 | hashdata_invert_komaster(Hash_data *hd, int komaster) |
| 153 | { |
| 154 | hashdata_xor(*hd, komaster_hash[komaster]); |
| 155 | } |
| 156 | |
| 157 | /* Set or remove the komaster position in the hash data. */ |
| 158 | void |
| 159 | hashdata_invert_kom_pos(Hash_data *hd, int kom_pos) |
| 160 | { |
| 161 | hashdata_xor(*hd, kom_pos_hash[kom_pos]); |
| 162 | } |
| 163 | |
| 164 | /* Calculate a transformation invariant hashvalue. */ |
| 165 | void |
| 166 | hashdata_calc_orientation_invariant(Hash_data *hd, Intersection *p, int ko_pos) |
| 167 | { |
| 168 | int pos; |
| 169 | int rot; |
| 170 | Hash_data hd_rot; |
| 171 | |
| 172 | for (rot = 0; rot < 8; rot++) { |
| 173 | hashdata_clear(&hd_rot); |
| 174 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 175 | if (p[pos] == WHITE) |
| 176 | hashdata_xor(hd_rot, white_hash[rotate1(pos, rot)]); |
| 177 | else if (p[pos] == BLACK) |
| 178 | hashdata_xor(hd_rot, black_hash[rotate1(pos, rot)]); |
| 179 | } |
| 180 | |
| 181 | if (ko_pos != NO_MOVE) |
| 182 | hashdata_xor(hd_rot, ko_hash[rotate1(ko_pos, rot)]); |
| 183 | |
| 184 | if (rot == 0 || hashdata_is_smaller(hd_rot, *hd)) |
| 185 | *hd = hd_rot; |
| 186 | } |
| 187 | } |
| 188 | |
| 189 | /* Compute hash value to identify the goal area. */ |
| 190 | Hash_data |
| 191 | goal_to_hashvalue(const signed char *goal) |
| 192 | { |
| 193 | int pos; |
| 194 | Hash_data return_value; |
| 195 | |
| 196 | hashdata_clear(&return_value); |
| 197 | |
| 198 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) |
| 199 | if (ON_BOARD(pos) && goal[pos]) |
| 200 | hashdata_xor(return_value, goal_hash[pos]); |
| 201 | |
| 202 | return return_value; |
| 203 | } |
| 204 | |
| 205 | |
| 206 | #define HASHVALUE_NUM_DIGITS (1 + (CHAR_BIT * SIZEOF_HASHVALUE - 1) / 4) |
| 207 | #define BUFFER_SIZE (1 + NUM_HASHVALUES * HASHVALUE_NUM_DIGITS) |
| 208 | char * |
| 209 | hashdata_to_string(Hash_data *hashdata) |
| 210 | { |
| 211 | static char buffer[BUFFER_SIZE]; |
| 212 | int n = 0; |
| 213 | int k; |
| 214 | |
| 215 | /* Loop backwards for consistency between 32 and 64 bit platforms. */ |
| 216 | for (k = NUM_HASHVALUES - 1; k >= 0; k--) { |
| 217 | n += sprintf(buffer + n, HASHVALUE_PRINT_FORMAT, |
| 218 | HASHVALUE_NUM_DIGITS, hashdata->hashval[k]); |
| 219 | gg_assert(n < BUFFER_SIZE); |
| 220 | } |
| 221 | |
| 222 | return buffer; |
| 223 | } |
| 224 | |
| 225 | #if NUM_HASHVALUES > 2 |
| 226 | int |
| 227 | hashdata_is_equal_func(Hash_data *hd1, Hash_data *hd2) |
| 228 | { |
| 229 | int i; |
| 230 | for (i = 0; i < NUM_HASHVALUES; i++) |
| 231 | if (hd1->hashval[i] != hd2->hashval[i]) |
| 232 | return 0; |
| 233 | |
| 234 | return 1; |
| 235 | } |
| 236 | |
| 237 | int |
| 238 | hashdata_is_smaller_func(Hash_data *hd1, Hash_data *hd2) |
| 239 | { |
| 240 | int i; |
| 241 | for (i = 0; i < NUM_HASHVALUES; i++) |
| 242 | if (hd1->hashval[i] < hd2->hashval[i]) |
| 243 | return 1; |
| 244 | else if (hd1->hashval[i] > hd2->hashval[i]) |
| 245 | return 0; |
| 246 | |
| 247 | return 0; |
| 248 | } |
| 249 | #endif |
| 250 | |
| 251 | |
| 252 | /* |
| 253 | * Local Variables: |
| 254 | * tab-width: 8 |
| 255 | * c-basic-offset: 2 |
| 256 | * End: |
| 257 | */ |