forked from Shiloh/githaven
55 lines
1.4 KiB
Go
55 lines
1.4 KiB
Go
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// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package xz
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import (
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"hash"
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"hash/crc32"
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"hash/crc64"
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)
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// crc32Hash implements the hash.Hash32 interface with Sum returning the
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// crc32 value in little-endian encoding.
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type crc32Hash struct {
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hash.Hash32
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}
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// Sum returns the crc32 value as little endian.
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func (h crc32Hash) Sum(b []byte) []byte {
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p := make([]byte, 4)
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putUint32LE(p, h.Hash32.Sum32())
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b = append(b, p...)
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return b
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}
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// newCRC32 returns a CRC-32 hash that returns the 64-bit value in
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// little-endian encoding using the IEEE polynomial.
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func newCRC32() hash.Hash {
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return crc32Hash{Hash32: crc32.NewIEEE()}
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}
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// crc64Hash implements the Hash64 interface with Sum returning the
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// CRC-64 value in little-endian encoding.
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type crc64Hash struct {
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hash.Hash64
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}
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// Sum returns the CRC-64 value in little-endian encoding.
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func (h crc64Hash) Sum(b []byte) []byte {
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p := make([]byte, 8)
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putUint64LE(p, h.Hash64.Sum64())
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b = append(b, p...)
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return b
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}
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// crc64Table is used to create a CRC-64 hash.
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var crc64Table = crc64.MakeTable(crc64.ECMA)
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// newCRC64 returns a CRC-64 hash that returns the 64-bit value in
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// little-endian encoding using the ECMA polynomial.
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func newCRC64() hash.Hash {
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return crc64Hash{Hash64: crc64.New(crc64Table)}
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}
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