1/* 2 * $Id: mt19937db.c,v 12.9 2008/03/12 19:23:38 mbrey Exp $ 3 */ 4#include "db_config.h" 5 6#include "db_int.h" 7#include "dbinc/crypto.h" 8#include "dbinc/hmac.h" 9 10/* A C-program for MT19937: Integer version (1999/10/28) */ 11/* genrand() generates one pseudorandom unsigned integer (32bit) */ 12/* which is uniformly distributed among 0 to 2^32-1 for each */ 13/* call. sgenrand(seed) sets initial values to the working area */ 14/* of 624 words. Before genrand(), sgenrand(seed) must be */ 15/* called once. (seed is any 32-bit integer.) */ 16/* Coded by Takuji Nishimura, considering the suggestions by */ 17/* Topher Cooper and Marc Rieffel in July-Aug. 1997. */ 18 19/* This library is free software under the Artistic license: */ 20/* see the file COPYING distributed together with this code. */ 21/* For the verification of the code, its output sequence file */ 22/* mt19937int.out is attached (2001/4/2) */ 23 24/* Copyright (C) 1997, 1999 Makoto Matsumoto and Takuji Nishimura. */ 25/* Any feedback is very welcome. For any question, comments, */ 26/* see http://www.math.keio.ac.jp/matumoto/emt.html or email */ 27/* matumoto@math.keio.ac.jp */ 28 29/* REFERENCE */ 30/* M. Matsumoto and T. Nishimura, */ 31/* "Mersenne Twister: A 623-Dimensionally Equidistributed Uniform */ 32/* Pseudo-Random Number Generator", */ 33/* ACM Transactions on Modeling and Computer Simulation, */ 34/* Vol. 8, No. 1, January 1998, pp 3--30. */ 35 36/* Period parameters */ 37#define N 624 38#define M 397 39#define MATRIX_A 0x9908b0df /* constant vector a */ 40#define UPPER_MASK 0x80000000 /* most significant w-r bits */ 41#define LOWER_MASK 0x7fffffff /* least significant r bits */ 42 43/* Tempering parameters */ 44#define TEMPERING_MASK_B 0x9d2c5680 45#define TEMPERING_MASK_C 0xefc60000 46#define TEMPERING_SHIFT_U(y) (y >> 11) 47#define TEMPERING_SHIFT_S(y) (y << 7) 48#define TEMPERING_SHIFT_T(y) (y << 15) 49#define TEMPERING_SHIFT_L(y) (y >> 18) 50 51static void __db_sgenrand __P((unsigned long, unsigned long *, int *)); 52#ifdef NOT_USED 53static void __db_lsgenrand __P((unsigned long *, unsigned long *, int *)); 54#endif 55static unsigned long __db_genrand __P((ENV *)); 56 57/* 58 * __db_generate_iv -- 59 * Generate an initialization vector (IV) 60 * 61 * PUBLIC: int __db_generate_iv __P((ENV *, u_int32_t *)); 62 */ 63int 64__db_generate_iv(env, iv) 65 ENV *env; 66 u_int32_t *iv; 67{ 68 int i, n, ret; 69 70 ret = 0; 71 n = DB_IV_BYTES / sizeof(u_int32_t); 72 MUTEX_LOCK(env, env->mtx_mt); 73 if (env->mt == NULL) { 74 if ((ret = __os_calloc(env, 1, N*sizeof(unsigned long), 75 &env->mt)) != 0) 76 return (ret); 77 /* mti==N+1 means mt[N] is not initialized */ 78 env->mti = N + 1; 79 } 80 for (i = 0; i < n; i++) { 81 /* 82 * We do not allow 0. If we get one just try again. 83 */ 84 do { 85 iv[i] = (u_int32_t)__db_genrand(env); 86 } while (iv[i] == 0); 87 } 88 89 MUTEX_UNLOCK(env, env->mtx_mt); 90 return (0); 91} 92 93/* Initializing the array with a seed */ 94static void 95__db_sgenrand(seed, mt, mtip) 96 unsigned long seed; 97 unsigned long mt[]; 98 int *mtip; 99{ 100 int i; 101 102 DB_ASSERT(NULL, seed != 0); 103 for (i=0;i<N;i++) { 104 mt[i] = seed & 0xffff0000; 105 seed = 69069 * seed + 1; 106 mt[i] |= (seed & 0xffff0000) >> 16; 107 seed = 69069 * seed + 1; 108 } 109 *mtip = N; 110} 111 112#ifdef NOT_USED 113/* Initialization by "sgenrand()" is an example. Theoretically, */ 114/* there are 2^19937-1 possible states as an intial state. */ 115/* This function allows to choose any of 2^19937-1 ones. */ 116/* Essential bits in "seed_array[]" is following 19937 bits: */ 117/* (seed_array[0]&UPPER_MASK), seed_array[1], ..., seed_array[N-1]. */ 118/* (seed_array[0]&LOWER_MASK) is discarded. */ 119/* Theoretically, */ 120/* (seed_array[0]&UPPER_MASK), seed_array[1], ..., seed_array[N-1] */ 121/* can take any values except all zeros. */ 122static void 123__db_lsgenrand(seed_array, mt, mtip) 124 unsigned long seed_array[]; 125 unsigned long mt[]; 126 int *mtip; 127 /* the length of seed_array[] must be at least N */ 128{ 129 int i; 130 131 for (i=0;i<N;i++) 132 mt[i] = seed_array[i]; 133 *mtip=N; 134} 135#endif 136 137static unsigned long 138__db_genrand(env) 139 ENV *env; 140{ 141 db_timespec ts; 142 unsigned long y; 143 static unsigned long mag01[2]={0x0, MATRIX_A}; 144 /* mag01[x] = x * MATRIX_A for x=0,1 */ 145 u_int32_t seed; 146 147 /* 148 * We are called with ENV->mtx_mt locked. 149 */ 150 if (env->mti >= N) { /* generate N words at one time */ 151 int kk; 152 153 if (env->mti == N+1) { /* if sgenrand() has not been called, */ 154 /* 155 * Seed the generator with the hashed time. The __db_mac 156 * function will return 4 bytes if we don't send in a key. 157 */ 158 do { 159 __os_gettime(env, &ts, 1); 160 __db_chksum(NULL, (u_int8_t *)&ts.tv_sec, 161 sizeof(ts.tv_sec), NULL, (u_int8_t *)&seed); 162 } while (seed == 0); 163 __db_sgenrand((unsigned long)seed, env->mt, &env->mti); 164 } 165 166 for (kk=0;kk<N-M;kk++) { 167 y = (env->mt[kk]&UPPER_MASK)|(env->mt[kk+1]&LOWER_MASK); 168 env->mt[kk] = env->mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1]; 169 } 170 for (;kk<N-1;kk++) { 171 y = (env->mt[kk]&UPPER_MASK)|(env->mt[kk+1]&LOWER_MASK); 172 env->mt[kk] = env->mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1]; 173 } 174 y = (env->mt[N-1]&UPPER_MASK)|(env->mt[0]&LOWER_MASK); 175 env->mt[N-1] = env->mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1]; 176 177 env->mti = 0; 178 } 179 180 y = env->mt[env->mti++]; 181 y ^= TEMPERING_SHIFT_U(y); 182 y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B; 183 y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C; 184 y ^= TEMPERING_SHIFT_L(y); 185 186 return y; 187} 188