1 files changed, 72 insertions, 0 deletions
diff --git a/vendor/github.com/pion/randutil/math.go b/vendor/github.com/pion/randutil/math.go
new file mode 100644
index 0000000..fbbf460
--- /dev/null
+++ b/vendor/github.com/pion/randutil/math.go
@@ -0,0 +1,72 @@
+package randutil
+
+import (
+	mrand "math/rand" // used for non-crypto unique ID and random port selection
+	"sync"
+	"time"
+)
+
+// MathRandomGenerator is a random generator for non-crypto usage.
+type MathRandomGenerator interface {
+	// Intn returns random integer within [0:n).
+	Intn(n int) int
+
+	// Uint32 returns random 32-bit unsigned integer.
+	Uint32() uint32
+
+	// Uint64 returns random 64-bit unsigned integer.
+	Uint64() uint64
+
+	// GenerateString returns ranom string using given set of runes.
+	// It can be used for generating unique ID to avoid name collision.
+	//
+	// Caution: DO NOT use this for cryptographic usage.
+	GenerateString(n int, runes string) string
+}
+
+type mathRandomGenerator struct {
+	r  *mrand.Rand
+	mu sync.Mutex
+}
+
+// NewMathRandomGenerator creates new mathmatical random generator.
+// Random generator is seeded by crypto random.
+func NewMathRandomGenerator() MathRandomGenerator {
+	seed, err := CryptoUint64()
+	if err != nil {
+		// crypto/rand is unavailable. Fallback to seed by time.
+		seed = uint64(time.Now().UnixNano())
+	}
+
+	return &mathRandomGenerator{r: mrand.New(mrand.NewSource(int64(seed)))}
+}
+
+func (g *mathRandomGenerator) Intn(n int) int {
+	g.mu.Lock()
+	v := g.r.Intn(n)
+	g.mu.Unlock()
+	return v
+}
+
+func (g *mathRandomGenerator) Uint32() uint32 {
+	g.mu.Lock()
+	v := g.r.Uint32()
+	g.mu.Unlock()
+	return v
+}
+
+func (g *mathRandomGenerator) Uint64() uint64 {
+	g.mu.Lock()
+	v := g.r.Uint64()
+	g.mu.Unlock()
+	return v
+}
+
+func (g *mathRandomGenerator) GenerateString(n int, runes string) string {
+	letters := []rune(runes)
+	b := make([]rune, n)
+	for i := range b {
+		b[i] = letters[g.Intn(len(letters))]
+	}
+	return string(b)
+}