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Diffstat (limited to 'src/pkg/rand/rand.go')
-rw-r--r-- | src/pkg/rand/rand.go | 179 |
1 files changed, 0 insertions, 179 deletions
diff --git a/src/pkg/rand/rand.go b/src/pkg/rand/rand.go deleted file mode 100644 index 459aed1db..000000000 --- a/src/pkg/rand/rand.go +++ /dev/null @@ -1,179 +0,0 @@ -// Copyright 2009 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -// Package rand implements pseudo-random number generators. -package rand - -import "sync" - -// A Source represents a source of uniformly-distributed -// pseudo-random int64 values in the range [0, 1<<63). -type Source interface { - Int63() int64 - Seed(seed int64) -} - -// NewSource returns a new pseudo-random Source seeded with the given value. -func NewSource(seed int64) Source { - var rng rngSource - rng.Seed(seed) - return &rng -} - -// A Rand is a source of random numbers. -type Rand struct { - src Source -} - -// New returns a new Rand that uses random values from src -// to generate other random values. -func New(src Source) *Rand { return &Rand{src} } - -// Seed uses the provided seed value to initialize the generator to a deterministic state. -func (r *Rand) Seed(seed int64) { r.src.Seed(seed) } - -// Int63 returns a non-negative pseudo-random 63-bit integer as an int64. -func (r *Rand) Int63() int64 { return r.src.Int63() } - -// Uint32 returns a pseudo-random 32-bit value as a uint32. -func (r *Rand) Uint32() uint32 { return uint32(r.Int63() >> 31) } - -// Int31 returns a non-negative pseudo-random 31-bit integer as an int32. -func (r *Rand) Int31() int32 { return int32(r.Int63() >> 32) } - -// Int returns a non-negative pseudo-random int. -func (r *Rand) Int() int { - u := uint(r.Int63()) - return int(u << 1 >> 1) // clear sign bit if int == int32 -} - -// Int63n returns, as an int64, a non-negative pseudo-random number in [0,n). -func (r *Rand) Int63n(n int64) int64 { - if n <= 0 { - return 0 - } - max := int64((1 << 63) - 1 - (1<<63)%uint64(n)) - v := r.Int63() - for v > max { - v = r.Int63() - } - return v % n -} - -// Int31n returns, as an int32, a non-negative pseudo-random number in [0,n). -func (r *Rand) Int31n(n int32) int32 { - if n <= 0 { - return 0 - } - max := int32((1 << 31) - 1 - (1<<31)%uint32(n)) - v := r.Int31() - for v > max { - v = r.Int31() - } - return v % n -} - -// Intn returns, as an int, a non-negative pseudo-random number in [0,n). -func (r *Rand) Intn(n int) int { - if n <= 1<<31-1 { - return int(r.Int31n(int32(n))) - } - return int(r.Int63n(int64(n))) -} - -// Float64 returns, as a float64, a pseudo-random number in [0.0,1.0). -func (r *Rand) Float64() float64 { return float64(r.Int63()) / (1 << 63) } - -// Float32 returns, as a float32, a pseudo-random number in [0.0,1.0). -func (r *Rand) Float32() float32 { return float32(r.Float64()) } - -// Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n). -func (r *Rand) Perm(n int) []int { - m := make([]int, n) - for i := 0; i < n; i++ { - m[i] = i - } - for i := 0; i < n; i++ { - j := r.Intn(i + 1) - m[i], m[j] = m[j], m[i] - } - return m -} - -/* - * Top-level convenience functions - */ - -var globalRand = New(&lockedSource{src: NewSource(1)}) - -// Seed uses the provided seed value to initialize the generator to a deterministic state. -func Seed(seed int64) { globalRand.Seed(seed) } - -// Int63 returns a non-negative pseudo-random 63-bit integer as an int64. -func Int63() int64 { return globalRand.Int63() } - -// Uint32 returns a pseudo-random 32-bit value as a uint32. -func Uint32() uint32 { return globalRand.Uint32() } - -// Int31 returns a non-negative pseudo-random 31-bit integer as an int32. -func Int31() int32 { return globalRand.Int31() } - -// Int returns a non-negative pseudo-random int. -func Int() int { return globalRand.Int() } - -// Int63n returns, as an int64, a non-negative pseudo-random number in [0,n). -func Int63n(n int64) int64 { return globalRand.Int63n(n) } - -// Int31n returns, as an int32, a non-negative pseudo-random number in [0,n). -func Int31n(n int32) int32 { return globalRand.Int31n(n) } - -// Intn returns, as an int, a non-negative pseudo-random number in [0,n). -func Intn(n int) int { return globalRand.Intn(n) } - -// Float64 returns, as a float64, a pseudo-random number in [0.0,1.0). -func Float64() float64 { return globalRand.Float64() } - -// Float32 returns, as a float32, a pseudo-random number in [0.0,1.0). -func Float32() float32 { return globalRand.Float32() } - -// Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n). -func Perm(n int) []int { return globalRand.Perm(n) } - -// NormFloat64 returns a normally distributed float64 in the range -// [-math.MaxFloat64, +math.MaxFloat64] with -// standard normal distribution (mean = 0, stddev = 1). -// To produce a different normal distribution, callers can -// adjust the output using: -// -// sample = NormFloat64() * desiredStdDev + desiredMean -// -func NormFloat64() float64 { return globalRand.NormFloat64() } - -// ExpFloat64 returns an exponentially distributed float64 in the range -// (0, +math.MaxFloat64] with an exponential distribution whose rate parameter -// (lambda) is 1 and whose mean is 1/lambda (1). -// To produce a distribution with a different rate parameter, -// callers can adjust the output using: -// -// sample = ExpFloat64() / desiredRateParameter -// -func ExpFloat64() float64 { return globalRand.ExpFloat64() } - -type lockedSource struct { - lk sync.Mutex - src Source -} - -func (r *lockedSource) Int63() (n int64) { - r.lk.Lock() - n = r.src.Int63() - r.lk.Unlock() - return -} - -func (r *lockedSource) Seed(seed int64) { - r.lk.Lock() - r.src.Seed(seed) - r.lk.Unlock() -} |