go/src/cmd/internal/hash/hash.go

57 lines
1.4 KiB
Go

// Copyright 2024 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 hash implements hash functions used in the compiler toolchain.
package hash
import (
"crypto/md5"
"crypto/sha1"
"crypto/sha256"
"hash"
)
const (
// Size32 is the size of 32 bytes hash checksum.
Size32 = sha256.Size
// Size20 is the size of 20 bytes hash checksum.
Size20 = sha1.Size
// Size16 is the size of 16 bytes hash checksum.
Size16 = md5.Size
)
// New32 returns a new [hash.Hash] computing the 32 bytes hash checksum.
func New32() hash.Hash {
h := sha256.New()
_, _ = h.Write([]byte{1}) // make this hash different from sha256
return h
}
// New20 returns a new [hash.Hash] computing the 20 bytes hash checksum.
func New20() hash.Hash {
return sha1.New()
}
// New16 returns a new [hash.Hash] computing the 16 bytes hash checksum.
func New16() hash.Hash {
return md5.New()
}
// Sum32 returns the 32 bytes checksum of the data.
func Sum32(data []byte) [Size32]byte {
sum := sha256.Sum256(data)
sum[0] ^= 1 // make this hash different from sha256
return sum
}
// Sum20 returns the 20 bytes checksum of the data.
func Sum20(data []byte) [Size20]byte {
return sha1.Sum(data)
}
// Sum16 returns the 16 bytes checksum of the data.
func Sum16(data []byte) [Size16]byte {
return md5.Sum(data)
}