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author | Wim <wim@42.be> | 2020-08-10 00:29:54 +0200 |
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committer | GitHub <noreply@github.com> | 2020-08-10 00:29:54 +0200 |
commit | 4e50fd864921c556988c919269448efdb90fa961 (patch) | |
tree | a3625f03f8de3c4f3841364000a4ea3aa42c1533 /vendor/google.golang.org/protobuf/internal/detrand | |
parent | dfdffa0027334e55ce213fc6eb62206dbf48baf6 (diff) | |
download | matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.tar.gz matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.tar.bz2 matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.zip |
Use mattermost v5 module (#1192)
Diffstat (limited to 'vendor/google.golang.org/protobuf/internal/detrand')
-rw-r--r-- | vendor/google.golang.org/protobuf/internal/detrand/rand.go | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/vendor/google.golang.org/protobuf/internal/detrand/rand.go b/vendor/google.golang.org/protobuf/internal/detrand/rand.go new file mode 100644 index 00000000..a904dd1f --- /dev/null +++ b/vendor/google.golang.org/protobuf/internal/detrand/rand.go @@ -0,0 +1,61 @@ +// 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() +} |