| package rand |
| |
| import ( |
| "math/rand" |
| "sync" |
| ) |
| |
| // Int returns a non-negative pseudo-random int. |
| func Int() int { return pseudo.Int() } |
| |
| // Intn returns, as an int, a non-negative pseudo-random number in [0,n). |
| // It panics if n <= 0. |
| func Intn(n int) int { return pseudo.Intn(n) } |
| |
| // Int63n returns, as an int64, a non-negative pseudo-random number in [0,n). |
| // It panics if n <= 0. |
| func Int63n(n int64) int64 { return pseudo.Int63n(n) } |
| |
| // Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n). |
| func Perm(n int) []int { return pseudo.Perm(n) } |
| |
| // Seed uses the provided seed value to initialize the default Source to a |
| // deterministic state. If Seed is not called, the generator behaves as if |
| // seeded by Seed(1). |
| func Seed(n int64) { pseudo.Seed(n) } |
| |
| var pseudo = rand.New(&source{src: rand.NewSource(1)}) |
| |
| type source struct { |
| src rand.Source |
| mu sync.Mutex |
| } |
| |
| func (s *source) Int63() int64 { |
| s.mu.Lock() |
| n := s.src.Int63() |
| s.mu.Unlock() |
| return n |
| } |
| |
| func (s *source) Seed(seed int64) { |
| s.mu.Lock() |
| s.src.Seed(seed) |
| s.mu.Unlock() |
| } |
| |
| // Shuffle pseudo-randomizes the order of elements. |
| // n is the number of elements. |
| // swap swaps the elements with indexes i and j. |
| func Shuffle(n int, swap func(i, j int)) { pseudo.Shuffle(n, swap) } |