Hulk did something

[bytom/vapor.git] / vendor / github.com / tendermint / tmlibs / common / random.go

diff --git a/vendor/github.com/tendermint/tmlibs/common/random.go b/vendor/github.com/tendermint/tmlibs/common/random.go
new file mode 100644 (file)
index 0000000..bcb8154
--- /dev/null
+++ b/vendor/github.com/tendermint/tmlibs/common/random.go
@@ -0,0 +1,68 @@
+package common
+
+import (
+       crand "crypto/rand"
+       "math/rand"
+)
+
+const (
+       strChars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" // 62 characters
+)
+
+func init() {
+       b := cRandBytes(8)
+       var seed uint64
+       for i := 0; i < 8; i++ {
+               seed |= uint64(b[i])
+               seed <<= 8
+       }
+       rand.Seed(int64(seed))
+}
+
+// Constructs an alphanumeric string of given length.
+func RandStr(length int) string {
+       chars := []byte{}
+MAIN_LOOP:
+       for {
+               val := rand.Int63()
+               for i := 0; i < 10; i++ {
+                       v := int(val & 0x3f) // rightmost 6 bits
+                       if v >= 62 {         // only 62 characters in strChars
+                               val >>= 6
+                               continue
+                       } else {
+                               chars = append(chars, strChars[v])
+                               if len(chars) == length {
+                                       break MAIN_LOOP
+                               }
+                               val >>= 6
+                       }
+               }
+       }
+
+       return string(chars)
+}
+
+func RandInt() int {
+       return rand.Int()
+}
+
+func RandBytes(n int) []byte {
+       bs := make([]byte, n)
+       for i := 0; i < n; i++ {
+               bs[i] = byte(rand.Intn(256))
+       }
+       return bs
+}
+
+// NOTE: This relies on the os's random number generator.
+// For real security, we should salt that with some seed.
+// See github.com/tendermint/go-crypto for a more secure reader.
+func cRandBytes(numBytes int) []byte {
+       b := make([]byte, numBytes)
+       _, err := crand.Read(b)
+       if err != nil {
+               PanicCrisis(err)
+       }
+       return b
+}