Suppress playing of book moves with weight 0

[xboard.git] / book.c

diff --git a/book.c b/book.c
index 9b02936..4f389ac 100644 (file)
--- a/book.c
+++ b/book.c
@@ -36,6 +36,7 @@
 
 #include "common.h"
 #include "backend.h"
+#include "moves.h"
 
 #ifdef _MSC_VER
   typedef unsigned __int64 uint64;
@@ -276,17 +277,21 @@ uint64 *RandomTurn      =Random64+780;
 uint64 hash(int moveNr)
 {
     int r, f, p_enc, squareNr, pieceGroup;
-    uint64 key=0, Zobrist;
+    uint64 key=0, holdingsKey=0, Zobrist;
 
-    for(f=BOARD_LEFT; f<BOARD_RGHT; f++){
+    for(f=0; f<BOARD_WIDTH; f++){
         for(r=0; r<BOARD_HEIGHT;r++){
             ChessSquare p = boards[moveNr][r][f];
+           if(f == BOARD_LEFT-1 || f == BOARD_RGHT) continue; // between board and holdings
             if(p != EmptySquare){
                    int j = (int)p;
                    j -= (j >= (int)BlackPawn) ? (int)BlackPawn :(int)WhitePawn;
                    if(j > (int)WhiteQueen) j++;  // make space for King
                    if(j > (int) WhiteKing) j = (int)WhiteQueen + 1;
                    p_enc = 2*j + ((int)p < (int)BlackPawn);
+                   // holdings squares get nmbers immediately after board; first left, then right holdings
+                   if(f == BOARD_LEFT-2) squareNr = (BOARD_RGHT - BOARD_LEFT)*BOARD_HEIGHT + r; else
+                   if(f == BOARD_RGHT+1) squareNr = (BOARD_RGHT - BOARD_LEFT + 1)*BOARD_HEIGHT + r; else
                    squareNr = (BOARD_RGHT - BOARD_LEFT)*r + (f - BOARD_LEFT);
                    // note that in normal Chess squareNr < 64 and p_enc < 12. The following code
                    // maps other pieces and squares in this range, and then modify the corresponding
@@ -306,11 +311,13 @@ uint64 hash(int moveNr)
                                break;
                    }
                    if(squareNr >= 64) Zobrist = (Zobrist << 8) ^ (Zobrist >> 56);
+                   // holdings have separate (additive) key, to encode presence of multiple pieces on same square
+                   if(f == BOARD_LEFT-2) holdingsKey += Zobrist * boards[moveNr][r][f+1]; else
+                   if(f == BOARD_RGHT+1) holdingsKey += Zobrist * boards[moveNr][r][f-1]; else
                 key ^= Zobrist;
             }
         }
     }
-    // Holdings not implemented yet!
 
     if(boards[moveNr][CASTLING][2] != NoRights) {
        if(boards[moveNr][CASTLING][0] != NoRights) key^=RandomCastle[0];
@@ -341,7 +348,7 @@ uint64 hash(int moveNr)
     if(WhiteOnMove(moveNr)){
         key^=RandomTurn[0];
     }
-    return key;
+    return key + holdingsKey;
 }
 
 #define MOVE_BUF 100
@@ -527,6 +534,7 @@ char *ProbeBook(int moveNr, char *book)
     for(i=0; i<count; i++){
         total_weight += entries[i].weight;
     }
+    if(total_weight == 0) return NULL; // force book miss rather than playing moves with weight 0.
     j = (random() & 0xFFF) * total_weight >> 12; // create random < total_weight
     total_weight = 0;
     for(i=0; i<count; i++){
@@ -573,13 +581,14 @@ int TextToMoves(char *text, int moveNum, entry_t *entries)
        float dummy;
        int width = BOARD_RGHT - BOARD_LEFT;
 
+       entries[0].key = hashKey; // make sure key is returned even if no moves
        while((i=sscanf(text, "%f%%%d", &dummy, &w))==2 || (i=sscanf(text, "%d", &w))==1) {
            if(i == 2) text = strchr(text, '%') + 1;  // skip percentage
            if(w == 1) text = strstr(text, "1 ") + 2; // skip weight that could be recognized as move number one
            valid = ParseOneMove(text, moveNum, &moveType, &fromX, &fromY, &toX, &toY, &promoChar);
            text = strstr(text, yy_textstr) + strlen(yy_textstr); // skip what we parsed
            if(!valid || moveType != NormalMove) continue;
-           if(*text == ' ' && sscanf(text+1, "{%d/%d}", &entries[count].learnPoints, &entries[count].learnCount) == 2) {
+           if(*text == ' ' && sscanf(text+1, "{%hd/%hd}", &entries[count].learnPoints, &entries[count].learnCount) == 2) {
                text = strchr(text+1, '}') + 1;
            } else {
                entries[count].learnPoints = 0;
@@ -587,8 +596,10 @@ int TextToMoves(char *text, int moveNum, entry_t *entries)
            }
            to = toX + toY * width;
            from = fromX + fromY * width;
-           // TODO: promotions, drops
-           entries[count].move = to + from * width * BOARD_HEIGHT;
+           for(i=0; promote_pieces[i]; i++) if(promote_pieces[i] == promoChar) break;
+           if(!promote_pieces[i]) i = 0;
+           if(fromY == DROP_RANK) i = 8, from = ToUpper(PieceToChar(fromX)) - '@';
+           entries[count].move = to + (i * width * BOARD_HEIGHT + from) * width * BOARD_HEIGHT;
            entries[count].key  = hashKey;
            entries[count].weight = w;
            count++;
@@ -642,11 +653,11 @@ void SaveToBook(char *text)
     int count = TextToMoves(text, currentMove, entries);
     int offset, i, len1=0, len2, readpos=0, writepos=0;
     FILE *f;
-    if(!count) return;
+    if(!count && !currentCount) return;
     f=fopen(appData.polyglotBook, "rb+");
     if(!f){    DisplayError("Polyglot book not valid", 0); return; }
     offset=find_key(f, entries[0].key, &entry);
-    if(entries[0].key != entry.key) {
+    if(entries[0].key != entry.key && currentCount) {
          DisplayError("Hash keys are different", 0);
          fclose(f);
          return;
@@ -671,3 +682,4 @@ void SaveToBook(char *text)
     }
     fclose(f);
 }
+