Split mt19937.c

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67023 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 158 insertions, 0 deletions

diff --git a/missing/mt19937.c b/missing/mt19937.c
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+/*
+This is based on trimmed version of MT19937.  To get the original version,
+contact <http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html>.
+
+The original copyright notice follows.
+
+   A C-program for MT19937, with initialization improved 2002/2/10.
+   Coded by Takuji Nishimura and Makoto Matsumoto.
+   This is a faster version by taking Shawn Cokus's optimization,
+   Matthe Bellew's simplification, Isaku Wada's real version.
+
+   Before using, initialize the state by using init_genrand(mt, seed)
+   or init_by_array(mt, init_key, key_length).
+
+   Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+     1. Redistributions of source code must retain the above copyright
+        notice, this list of conditions and the following disclaimer.
+
+     2. Redistributions in binary form must reproduce the above copyright
+        notice, this list of conditions and the following disclaimer in the
+        documentation and/or other materials provided with the distribution.
+
+     3. The names of its contributors may not be used to endorse or promote
+        products derived from this software without specific prior written
+        permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+   Any feedback is very welcome.
+   http://www.math.keio.ac.jp/matumoto/emt.html
+   email: matumoto@math.keio.ac.jp
+*/
+
+/* Period parameters */
+#define N 624
+#define M 397
+#define MATRIX_A 0x9908b0dfU	/* constant vector a */
+#define UMASK 0x80000000U	/* most significant w-r bits */
+#define LMASK 0x7fffffffU	/* least significant r bits */
+#define MIXBITS(u,v) ( ((u) & UMASK) | ((v) & LMASK) )
+#define TWIST(u,v) ((MIXBITS((u),(v)) >> 1) ^ ((v)&1U ? MATRIX_A : 0U))
+
+enum {MT_MAX_STATE = N};
+
+struct MT {
+    /* assume int is enough to store 32bits */
+    uint32_t state[N]; /* the array for the state vector  */
+    uint32_t *next;
+    int left;
+};
+
+#define genrand_initialized(mt) ((mt)->next != 0)
+#define uninit_genrand(mt) ((mt)->next = 0)
+
+NO_SANITIZE("unsigned-integer-overflow", static void init_genrand(struct MT *mt, unsigned int s));
+NO_SANITIZE("unsigned-integer-overflow", static void init_by_array(struct MT *mt, const uint32_t init_key[], int key_length));
+
+/* initializes state[N] with a seed */
+static void
+init_genrand(struct MT *mt, unsigned int s)
+{
+    int j;
+    mt->state[0] = s & 0xffffffffU;
+    for (j=1; j<N; j++) {
+        mt->state[j] = (1812433253U * (mt->state[j-1] ^ (mt->state[j-1] >> 30)) + j);
+        /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
+        /* In the previous versions, MSBs of the seed affect   */
+        /* only MSBs of the array state[].                     */
+        /* 2002/01/09 modified by Makoto Matsumoto             */
+        mt->state[j] &= 0xffffffff;  /* for >32 bit machines */
+    }
+    mt->left = 1;
+    mt->next = mt->state + N;
+}
+
+/* initialize by an array with array-length */
+/* init_key is the array for initializing keys */
+/* key_length is its length */
+/* slight change for C++, 2004/2/26 */
+static void
+init_by_array(struct MT *mt, const uint32_t init_key[], int key_length)
+{
+    int i, j, k;
+    init_genrand(mt, 19650218U);
+    i=1; j=0;
+    k = (N>key_length ? N : key_length);
+    for (; k; k--) {
+        mt->state[i] = (mt->state[i] ^ ((mt->state[i-1] ^ (mt->state[i-1] >> 30)) * 1664525U))
+          + init_key[j] + j; /* non linear */
+        mt->state[i] &= 0xffffffffU; /* for WORDSIZE > 32 machines */
+        i++; j++;
+        if (i>=N) { mt->state[0] = mt->state[N-1]; i=1; }
+        if (j>=key_length) j=0;
+    }
+    for (k=N-1; k; k--) {
+        mt->state[i] = (mt->state[i] ^ ((mt->state[i-1] ^ (mt->state[i-1] >> 30)) * 1566083941U))
+          - i; /* non linear */
+        mt->state[i] &= 0xffffffffU; /* for WORDSIZE > 32 machines */
+        i++;
+        if (i>=N) { mt->state[0] = mt->state[N-1]; i=1; }
+    }
+
+    mt->state[0] = 0x80000000U; /* MSB is 1; assuring non-zero initial array */
+}
+
+static void
+next_state(struct MT *mt)
+{
+    uint32_t *p = mt->state;
+    int j;
+
+    mt->left = N;
+    mt->next = mt->state;
+
+    for (j=N-M+1; --j; p++)
+        *p = p[M] ^ TWIST(p[0], p[1]);
+
+    for (j=M; --j; p++)
+        *p = p[M-N] ^ TWIST(p[0], p[1]);
+
+    *p = p[M-N] ^ TWIST(p[0], mt->state[0]);
+}
+
+/* generates a random number on [0,0xffffffff]-interval */
+static unsigned int
+genrand_int32(struct MT *mt)
+{
+    /* mt must be initialized */
+    unsigned int y;
+
+    if (--mt->left <= 0) next_state(mt);
+    y = *mt->next++;
+
+    /* Tempering */
+    y ^= (y >> 11);
+    y ^= (y << 7) & 0x9d2c5680;
+    y ^= (y << 15) & 0xefc60000;
+    y ^= (y >> 18);
+
+    return y;
+}