mersenne_twister.go

package MersenneTwister

import(
    "sync"
)

type Generator struct{
    state [624]uint32
    index uint32
    generating sync.Mutex
}

func Init(a uint32) *Generator{
    var t Generator
    t.init(a)
    return &t
}

func (g *Generator) init(a uint32){
    g.generating.Lock()
    g.state[0] = a
    var i uint32 = 0
    for i=1; i<624; i++{
        g.state[i] = uint32(0x6c078965 * (g.state[i-1] ^
                    g.state[i-1]>>30) + i)
    }
    g.generating.Unlock()
}

func (g *Generator) Next() uint32{
    g.generating.Lock()
    if g.index == 0{
        g.generateNumbers()
    }
    y := g.state[g.index]
    g.index++
    g.index %= 624
    g.generating.Unlock()
    y ^= y>>11
    y ^= y<<7 & 0x9d2c5680
    y ^= y<<15 & 0xefc60000
    y ^= y>>18
    return y
}

func (g *Generator) generateNumbers(){
    var i uint32
    for i=0; i<624; i++{
        y := g.state[i]>>31 + g.state[(i+1)%624] & 0x7fffffff
        g.state[i] = g.state[(i+397)%624] ^ y>>1
        if y%2 == 1{
            g.state[i] ^= 0x9908b0df
        }
    }
}