ceph-csi/vendor/google.golang.org/protobuf/internal/detrand/rand.go
Niels de Vos 91774fc936 rebase: vendor dependencies for Vault API
Uses github.com/libopenstorage/secrets to communicate with Vault. This
removes the need for maintaining our own limited Vault APIs.

By adding the new dependency, several other packages got updated in the
process. Unused indirect dependencies have been removed from go.mod.

Signed-off-by: Niels de Vos <ndevos@redhat.com>
2020-11-29 04:03:59 +00:00

62 lines
1.5 KiB
Go

// Copyright 2018 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 detrand provides deterministically random functionality.
//
// The pseudo-randomness of these functions is seeded by the program binary
// itself and guarantees that the output does not change within a program,
// while ensuring that the output is unstable across different builds.
package detrand
import (
"encoding/binary"
"hash/fnv"
"os"
)
// Disable disables detrand such that all functions returns the zero value.
// This function is not concurrent-safe and must be called during program init.
func Disable() {
randSeed = 0
}
// Bool returns a deterministically random boolean.
func Bool() bool {
return randSeed%2 == 1
}
// randSeed is a best-effort at an approximate hash of the Go binary.
var randSeed = binaryHash()
func binaryHash() uint64 {
// Open the Go binary.
s, err := os.Executable()
if err != nil {
return 0
}
f, err := os.Open(s)
if err != nil {
return 0
}
defer f.Close()
// Hash the size and several samples of the Go binary.
const numSamples = 8
var buf [64]byte
h := fnv.New64()
fi, err := f.Stat()
if err != nil {
return 0
}
binary.LittleEndian.PutUint64(buf[:8], uint64(fi.Size()))
h.Write(buf[:8])
for i := int64(0); i < numSamples; i++ {
if _, err := f.ReadAt(buf[:], i*fi.Size()/numSamples); err != nil {
return 0
}
h.Write(buf[:])
}
return h.Sum64()
}