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DEFINITIONS

1. fits_in
2. place

   1 /*-
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek and Darren F. Provine.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  *      @(#)shapes.c    8.1 (Berkeley) 5/31/93
  33  */
  35 /*
  36  * Tetris shapes and related routines.
  37  *
  38  * Note that the first 7 are `well known'.
  39  */
  41 #include <sys/cdefs.h>
  42 #include "tetris.h"
  44 #define TL      -B_COLS-1       /* top left */
  45 #define TC      -B_COLS         /* top center */
  46 #define TR      -B_COLS+1       /* top right */
  47 #define ML      -1              /* middle left */
  48 #define MR      1               /* middle right */
  49 #define BL      B_COLS-1        /* bottom left */
  50 #define BC      B_COLS          /* bottom center */
  51 #define BR      B_COLS+1        /* bottom right */
  53 const struct shape shapes[] = {
  54         /* 0*/  { 7,    { TL, TC, MR, } },
  55         /* 1*/  { 8,    { TC, TR, ML, } },
  56         /* 2*/  { 9,    { ML, MR, BC, } },
  57         /* 3*/  { 3,    { TL, TC, ML, } },
  58         /* 4*/  { 12,   { ML, BL, MR, } },
  59         /* 5*/  { 15,   { ML, BR, MR, } },
  60         /* 6*/  { 18,   { ML, MR, 2   } },      /* sticks out */
  61         /* 7*/  { 0,    { TC, ML, BL, } },
  62         /* 8*/  { 1,    { TC, MR, BR, } },
  63         /* 9*/  { 10,   { TC, MR, BC, } },
  64         /*10*/  { 11,   { TC, ML, MR, } },
  65         /*11*/  { 2,    { TC, ML, BC, } },
  66         /*12*/  { 13,   { TC, BC, BR, } },
  67         /*13*/  { 14,   { TR, ML, MR, } },
  68         /*14*/  { 4,    { TL, TC, BC, } },
  69         /*15*/  { 16,   { TR, TC, BC, } },
  70         /*16*/  { 17,   { TL, MR, ML, } },
  71         /*17*/  { 5,    { TC, BC, BL, } },
  72         /*18*/  { 6,    { TC, BC, 2*B_COLS } }  /* sticks out */
  73 };
  75 /*
  76  * Return true iff the given shape fits in the given position,
  77  * taking the current board into account.
  78  */
  79 int
fits_in(const struct shape *shape, int pos)
  81 {
  82         const int *o = shape->off;
  84         if (board[pos] || board[pos + *o++] || board[pos + *o++] ||
board[pos + *o])
  86                 return 0;
  87         return 1;
  88 }
  90 /*
  91  * Write the given shape into the current board, turning it on
  92  * if `onoff' is 1, and off if `onoff' is 0.
  93  */
  94 void
place(const struct shape *shape, int pos, cell onoff)
  96 {
  97         const int *o = shape->off;
board[pos] = onoff;
board[pos + *o++] = onoff;
board[pos + *o++] = onoff;
board[pos + *o] = onoff;
 103 }