随机数生成优化

rand/rand_generator.go

@@ -0,0 +1,102 @@
+package rand
+
+import (
+	mrnd "math/rand"
+	"runtime"
+	"sync/atomic"
+	"time"
+)
+
+var (
+	seed  = time.Now().UnixNano()                 // 随机数种子
+	souce = mrnd.NewSource(time.Now().UnixNano()) // 用于初始化的随机数生成器
+)
+
+type randGenerator struct {
+	source mrnd.Source
+	r      uint32
+}
+
+func NewRandGenerator() *randGenerator {
+	return &randGenerator{
+		source: mrnd.NewSource(getSeed()),
+	}
+}
+
+func getSeed() int64 {
+	seed ^= souce.Int63()
+	return seed
+}
+
+// Int63n returns, as an int64, a non-negative pseudo-random number in the half-open interval [0,n).
+// It panics if n <= 0.
+func (r *randGenerator) Int63n(n int64) int64 {
+	if n <= 0 {
+		panic("invalid argument to Int63n")
+	}
+	if n&(n-1) == 0 { // n is power of two, can mask
+		return r.Int63() & (n - 1)
+	}
+	max := int64((1 << 63) - 1 - (1<<63)%uint64(n))
+	v := r.Int63()
+	for v > max {
+		v = r.Int63()
+	}
+
+	return v % n
+}
+
+func (r *randGenerator) Int31() int32 {
+	return int32(r.Int63() >> 32)
+}
+
+func (r *randGenerator) Int31n(n int32) int32 {
+	if n <= 0 {
+		panic("invalid argument to Int31n")
+	}
+
+	if n&(n-1) == 0 { // n is power of two, can mask
+		return r.Int31() & (n - 1)
+	}
+	max := int32((1 << 31) - 1 - (1<<31)%uint32(n))
+	v := r.Int31()
+	for v > max {
+		v = r.Int31()
+	}
+	return v % n
+}
+
+func (r *randGenerator) Int() int {
+	u := uint(r.Int63())
+	return int(u << 1 >> 1) // clear sign bit if int == int32
+}
+
+// Intn returns, as an int, a non-negative pseudo-random number in the half-open interval [0,n).
+// It panics if n <= 0.
+func (r *randGenerator) Intn(n int) int {
+	if n <= 0 {
+		panic("invalid argument to Intn")
+	}
+	if n <= 1<<31-1 {
+		return int(r.Int31n(int32(n)))
+	}
+	return int(r.Int63n(int64(n)))
+}
+
+func (r *randGenerator) Int63() int64 {
+	r.lock()
+	i := r.source.Int63()
+	r.unlock()
+
+	return i
+}
+
+func (g *randGenerator) lock() {
+	for !atomic.CompareAndSwapUint32(&g.r, 0, 1) {
+		runtime.Gosched()
+	}
+}
+
+func (g *randGenerator) unlock() {
+	atomic.StoreUint32(&g.r, 0)
+}