rand.go

Documentation: github.com/redis/go-redis/v9/internal/rand

     1  package rand
     2  
     3  import (
     4  	"math/rand"
     5  	"sync"
     6  )
     7  
     8  // Int returns a non-negative pseudo-random int.
     9  func Int() int { return pseudo.Int() }
    10  
    11  // Intn returns, as an int, a non-negative pseudo-random number in [0,n).
    12  // It panics if n <= 0.
    13  func Intn(n int) int { return pseudo.Intn(n) }
    14  
    15  // Int63n returns, as an int64, a non-negative pseudo-random number in [0,n).
    16  // It panics if n <= 0.
    17  func Int63n(n int64) int64 { return pseudo.Int63n(n) }
    18  
    19  // Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n).
    20  func Perm(n int) []int { return pseudo.Perm(n) }
    21  
    22  // Seed uses the provided seed value to initialize the default Source to a
    23  // deterministic state. If Seed is not called, the generator behaves as if
    24  // seeded by Seed(1).
    25  func Seed(n int64) { pseudo.Seed(n) }
    26  
    27  var pseudo = rand.New(&source{src: rand.NewSource(1)})
    28  
    29  type source struct {
    30  	src rand.Source
    31  	mu  sync.Mutex
    32  }
    33  
    34  func (s *source) Int63() int64 {
    35  	s.mu.Lock()
    36  	n := s.src.Int63()
    37  	s.mu.Unlock()
    38  	return n
    39  }
    40  
    41  func (s *source) Seed(seed int64) {
    42  	s.mu.Lock()
    43  	s.src.Seed(seed)
    44  	s.mu.Unlock()
    45  }
    46  
    47  // Shuffle pseudo-randomizes the order of elements.
    48  // n is the number of elements.
    49  // swap swaps the elements with indexes i and j.
    50  func Shuffle(n int, swap func(i, j int)) { pseudo.Shuffle(n, swap) }
    51
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