Allow user castling in Mighty Lion

A large part of the castling code is implemented: MakeMove can perform it,
ParseMove can recognize it. The routine GenCastlings generates them,
but without paying attention to (moving through) check, and Highlight
marks the King's to-square in the color FEN.
 The castlings are only generated by ListMoves, added to the list used
for legality testing of input moves, though (and then only in variant lion).
Not yet in GenNonCaptures, so HaChu would never castle itself, but will
accept it if the user does so. It would even accept castling through check,
but the idea is that legality checking in the GUI would prevent the user
from entering that.

diff --git a/hachu.c b/hachu.c
index fdf5bb4..a0c878b 100644 (file)
--- a/hachu.c
+++ b/hachu.c
@@ -89,6 +89,7 @@
 #define PROMOTE (1<<2*SQLEN+1)     /* promotion bit in move   */\r
 #define SPECIAL  1400              /* start of special moves  */\r
 #define BURN    (SPECIAL + 96)     /* start of burn encodings */\r
+#define CASTLE  (SPECIAL + 100)    /* castling encodings      */\r
 #define STEP(X,Y) (BW*(X)+ (Y))\r
 #define SORTKEY(X) 0\r
 \r
@@ -498,7 +499,7 @@ Vector direction[] = { // clockwise!
   { 2,-1}\r
 };\r
 \r
-int epList[96], ep2List[96], toList[96], reverse[96];  // decoding tables for double and triple moves\r
+int epList[104], ep2List[104], toList[104], reverse[104];  // decoding tables for double and triple moves\r
 int kingStep[10], knightStep[10];         // raw tables for step vectors (indexed as -1 .. 8)\r
 int neighbors[9];   // similar to kingStep, but starts with null-step\r
 char fireFlags[10]; // flags for Fire-Demon presence (last two are dummies, which stay 0, for compactify)\r
@@ -959,6 +960,11 @@ Init (int var)
     toList[88+i] =   kStep[i]; epList[88+i] = 2*kStep[i];\r
   }\r
 \r
+  toList[100]   = BH - 2; epList[100]   = BH - 1; ep2List[100]   = BH - 3;\r
+  toList[100+1] =      2; epList[100+1] =      0; ep2List[100+1] =      3;\r
+  toList[100+2] = bsize - BH - 2; epList[100+2] = bsize - BH - 1; ep2List[100+2] = bsize - BH - 3;\r
+  toList[100+3] = bsize - BW + 2; epList[100+3] = bsize - BW;     ep2List[100+3] = bsize - BW + 3;\r
+\r
   // fill distance table\r
   for(i=0; i<2*BSIZE; i++) {\r
     distance[i] = 0;\r
@@ -1135,6 +1141,17 @@ MarkBurns (int x)
   for(r=b; r<=t-2; r++) rows[r] |= rows[r+1] | rows[r+2]; // smear vertically\r
 }\r
 \r
+void\r
+GenCastlings ()\r
+{ // castings for Lion Chess. Assumes board width = 8 and Kings on e-file, and K/R value = 280/300!\r
+    int f = BH>>1, t = CASTLE;\r
+    if(stm != WHITE) f += bsize - BW, t += 2;\r
+    if(p[board[f]].value = 280) {\r
+      if(p[board[f-4]].value == 300 && board[f-3] == EMPTY && board[f-2] == EMPTY && board[f-1] == EMPTY) moveStack[msp++] = f<<SQLEN | t+1;\r
+      if(p[board[f+3]].value == 300 && board[f+1] == EMPTY && board[f+2] == EMPTY) moveStack[msp++] = f<<SQLEN | t;\r
+    }\r
+}\r
+\r
 int\r
 GenNonCapts (int promoSuppress)\r
 {\r
@@ -1309,6 +1326,21 @@ MakeMove(Move m, UndoInfo *u)
   } else u->new = u->piece;\r
 \r
   if(u->to >= SPECIAL) { // two-step Lion move\r
+   if(u->to >= CASTLE) { // move Rook, faking it was an e.p. victim so that UnMake works automatically\r
+    u->epSquare  = epList[u->to - SPECIAL];\r
+    u->ep2Square = ep2List[u->to - SPECIAL];\r
+    u->epVictim[0] = board[u->epSquare];  // kludgy: fake that King e.p. captured the Rook!\r
+    u->epVictim[1] = board[u->ep2Square]; // should be EMPTY (but you never know, so save as well).\r
+    board[u->ep2Square] = u->epVictim[0]; // but put Rook back\r
+    board[u->epSquare]  = EMPTY;\r
+    p[u->epVictim[0]].pos = u->ep2Square;\r
+    p[u->epVictim[1]].pos = ABSENT;\r
+    u->to       = toList[u->to - SPECIAL];\r
+    hashKeyL ^= p[u->epVictim[0]].pieceKey * squareKey[u->epSquare];\r
+    hashKeyH ^= p[u->epVictim[0]].pieceKey * squareKey[u->epSquare+BH];\r
+    hashKeyL ^= p[u->epVictim[0]].pieceKey * squareKey[u->ep2Square];\r
+    hashKeyH ^= p[u->epVictim[0]].pieceKey * squareKey[u->ep2Square+BH];\r
+   } else {\r
     // take care of first e.p. victim\r
     u->epSquare = u->from + epList[u->to - SPECIAL]; // decode\r
     u->epVictim[0] = board[u->epSquare]; // remember for takeback\r
@@ -1335,6 +1367,7 @@ MakeMove(Move m, UndoInfo *u)
     hashKeyH ^= p[u->epVictim[1]].pieceKey * squareKey[u->ep2Square+BH];\r
     if(p[u->piece].value != LVAL && p[u->epVictim[0]].value == LVAL) deferred |= PROMOTE; // flag non-Lion x Lion\r
     cnt50 = 0; // double capture irreversible\r
+   }\r
   }\r
 \r
   if(u->fireMask & fireBoard[u->to]) { // we moved next to enemy Fire Demon (must be done after SPECIAL, to decode to-sqr)\r
@@ -2384,7 +2417,8 @@ MoveToText (MOVE move, int multiLine)
   char *promoChar = "";\r
   if(f == t) { sprintf(buf, "@@@@"); return buf; } // null-move notation in WB protocol\r
   buf[0] = '\0';\r
-  if(t >= SPECIAL) { // kludgy! Print as side effect non-standard WB command to remove victims from double-capture (breaks hint command!)\r
+  if(t >= SPECIAL) {\r
+   if(t < CASTLE) { // castling is printed as a single move, implying its side effects\r
     int e = f + epList[t - SPECIAL];\r
 //    printf("take %c%d\n", e%BW+'a', e/BW+ONE);\r
     sprintf(buf, "%c%d%c%d,", f%BW+'a', f/BW+ONE, e%BW+'a', e/BW+ONE); f = e;\r
@@ -2395,6 +2429,7 @@ MoveToText (MOVE move, int multiLine)
       sprintf(buf+strlen(buf), "%c%d%c%d,", f%BW+'a', f/BW+ONE, e%BW+'a', e/BW+ONE); f = e;\r
     if(multiLine) printf("move %s\n", buf), buf[0] = '\0';\r
     }\r
+   }\r
     t = g + toList[t - SPECIAL];\r
   }\r
   if(move & PROMOTE) promoChar = currentVariant == V_MAKRUK ? "m" : repDraws ? "q" : "+";\r
@@ -2425,7 +2460,8 @@ MapFromScratch(attacks);
   Search(-INF-1, INF+1, 0, QSdepth+1, 0, sup1 & ~PROMOTE, sup2, INF);\r
   postThinking++;\r
 \r
-  listStart = retFirst; listEnd = msp = retMSP;\r
+  listStart = retFirst; msp = retMSP;\r
+  if(currentVariant == V_LION) GenCastlings(); listEnd = msp;\r
 }\r
 \r
 MOVE\r
@@ -2451,6 +2487,11 @@ ParseMove (char *moveText)
       if(t == f + BW - 1) t2 = SPECIAL + 48; else\r
       if(t == f - BW + 1) t2 = SPECIAL + 20; else\r
       if(t == f - BW - 1) t2 = SPECIAL + 52; // fake double-move\r
+  } else if(currentVariant == V_LION && board[f] != EMPTY && p[board[f]].value == 280 && (t-f == 2 || f-t == 2)) { // castling\r
+      if(t == f+2 && f < BW) t2 = CASTLE;     else\r
+      if(t == f-2 && f < BW) t2 = CASTLE + 1; else\r
+      if(t == f+2 && f > BW) t2 = CASTLE + 2; else\r
+      if(t == f-2 && f > BW) t2 = CASTLE + 3;\r
   }\r
   ret = f<<SQLEN | t2;\r
   if(*moveText != '\n' && *moveText != '=') ret |= PROMOTE;\r
@@ -2500,6 +2541,7 @@ Highlight(char *coords)
   for(i=listStart; i<listEnd; i++) {\r
     if(sqr == (moveStack[i]>>SQLEN & SQUARE)) {\r
       int t = moveStack[i] & SQUARE;\r
+      if(t >= CASTLE) t = toList[t - SPECIAL]; else  // decode castling\r
       if(t >= SPECIAL) {\r
        int e = sqr + epList[t - SPECIAL]; // decode\r
        b[e] = 'C';\r