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// Copyright 2014-2019 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package xz
import (
"hash"
"hash/crc32"
"hash/crc64"
)
// crc32Hash implements the hash.Hash32 interface with Sum returning the
// crc32 value in little-endian encoding.
type crc32Hash struct {
hash.Hash32
}
// Sum returns the crc32 value as little endian.
func (h crc32Hash) Sum(b []byte) []byte {
p := make([]byte, 4)
putUint32LE(p, h.Hash32.Sum32())
b = append(b, p...)
return b
}
// newCRC32 returns a CRC-32 hash that returns the 64-bit value in
// little-endian encoding using the IEEE polynomial.
func newCRC32() hash.Hash {
return crc32Hash{Hash32: crc32.NewIEEE()}
}
// crc64Hash implements the Hash64 interface with Sum returning the
// CRC-64 value in little-endian encoding.
type crc64Hash struct {
hash.Hash64
}
// Sum returns the CRC-64 value in little-endian encoding.
func (h crc64Hash) Sum(b []byte) []byte {
p := make([]byte, 8)
putUint64LE(p, h.Hash64.Sum64())
b = append(b, p...)
return b
}
// crc64Table is used to create a CRC-64 hash.
var crc64Table = crc64.MakeTable(crc64.ECMA)
// newCRC64 returns a CRC-64 hash that returns the 64-bit value in
// little-endian encoding using the ECMA polynomial.
func newCRC64() hash.Hash {
return crc64Hash{Hash64: crc64.New(crc64Table)}
}
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