1 /* 2 * Copyright (c) 1988 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Timothy C. Stoehr. 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 static char sccsid[] = "@(#)random.c 5.3 (Berkeley) 6/1/90"; 39 #endif /* not lint */ 40 41 /* 42 * random.c 43 * 44 * This source herein may be modified and/or distributed by anybody who 45 * so desires, with the following restrictions: 46 * 1.) No portion of this notice shall be removed. 47 * 2.) Credit shall not be taken for the creation of this source. 48 * 3.) This code is not to be traded, sold, or used for personal 49 * gain or profit. 50 * 51 */ 52 53 static long rntb[32] = { 54 3, 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342, 55 0xde3b81e0, 0xdf0a6fb5, 0xf103bc02, 0x48f340fb, 0x7449e56b, 56 0xbeb1dbb0, 0xab5c5918, 0x946554fd, 0x8c2e680f, 0xeb3d799f, 57 0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, 0xe369735d, 58 0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc, 59 0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e, 60 0x8999220b, 0x27fb47b9 61 }; 62 63 static long *fptr = &rntb[4]; 64 static long *rptr = &rntb[1]; 65 static long *state = &rntb[1]; 66 static int rand_type = 3; 67 static int rand_deg = 31; 68 static int rand_sep = 3; 69 static long *end_ptr = &rntb[32]; 70 71 srrandom(x) 72 int x; 73 { 74 register int i; 75 long rrandom(); 76 77 state[0] = (long) x; 78 if (rand_type != 0) { 79 for (i = 1; i < rand_deg; i++) { 80 state[i] = 1103515245 * state[i - 1] + 12345; 81 } 82 fptr = &state[rand_sep]; 83 rptr = &state[0]; 84 for (i = 0; i < 10 * rand_deg; i++) { 85 (void) rrandom(); 86 } 87 } 88 } 89 90 long 91 rrandom() 92 { 93 long i; 94 95 if (rand_type == 0) { 96 i = state[0] = (state[0]*1103515245 + 12345) & 0x7fffffff; 97 } else { 98 *fptr += *rptr; 99 i = (*fptr >> 1) & 0x7fffffff; 100 if (++fptr >= end_ptr) { 101 fptr = state; 102 ++rptr; 103 } else { 104 if (++rptr >= end_ptr) { 105 rptr = state; 106 } 107 } 108 } 109 return(i); 110 } 111 112 get_rand(x, y) 113 register int x, y; 114 { 115 register int r, t; 116 long lr; 117 118 if (x > y) { 119 t = y; 120 y = x; 121 x = t; 122 } 123 lr = rrandom(); 124 lr &= (long) 0x00003fff; 125 r = (int) lr; 126 r = (r % ((y - x) + 1)) + x; 127 return(r); 128 } 129 130 rand_percent(percentage) 131 register int percentage; 132 { 133 return(get_rand(1, 100) <= percentage); 134 } 135 136 coin_toss() 137 { 138 139 return(((rrandom() & 01) ? 1 : 0)); 140 } 141