common/nullHasher.go

// Copyright © 2017 Microsoft <wastore@microsoft.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package common

import "hash"

// A hash.Hash implementation that does nothing
type nullHasher struct{}

func NewNullHasher() hash.Hash {
	return &nullHasher{}
}

func (*nullHasher) Write(p []byte) (n int, err error) {
	// noop
	return 0, nil
}

func (*nullHasher) Sum(b []byte) []byte {
	return make([]byte, 0)
}

func (*nullHasher) Reset() {
	// noop
}

func (*nullHasher) Size() int {
	return 0
}

func (*nullHasher) BlockSize() int {
	return 1
}