mirror of
https://github.com/minio/minio.git
synced 2024-12-27 15:45:55 -05:00
76 lines
1.7 KiB
Go
76 lines
1.7 KiB
Go
// Copyright 2009 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 crc32 implements the 32-bit cyclic redundancy check, or CRC-32,
|
|
// checksum. See http://en.wikipedia.org/wiki/Cyclic_redundancy_check for
|
|
// information.
|
|
package crc32c
|
|
|
|
import (
|
|
"hash"
|
|
"io"
|
|
)
|
|
|
|
// The size of a CRC-32 checksum in bytes.
|
|
const Size = 4
|
|
|
|
// digest represents the partial evaluation of a checksum.
|
|
type digest struct {
|
|
crc uint32
|
|
}
|
|
|
|
// New creates a new hash.Hash32 computing the CRC-32 checksum
|
|
// using the polynomial represented by the Table.
|
|
func New() hash.Hash32 {
|
|
return &digest{crc: 0}
|
|
}
|
|
|
|
func (d *digest) Size() int { return Size }
|
|
|
|
func (d *digest) BlockSize() int { return 1 }
|
|
|
|
func (d *digest) Sum(in []byte) []byte {
|
|
s := d.crc
|
|
return append(in, byte(s>>24), byte(s>>16), byte(s>>8), byte(s))
|
|
}
|
|
|
|
func (d *digest) Sum32() uint32 { return d.crc }
|
|
|
|
func (d *digest) Reset() { d.crc = 0 }
|
|
|
|
// Update returns the result of adding the bytes in p to the crc.
|
|
func (d *digest) update(crc uint32, p []byte) uint32 {
|
|
return updateCastanagoliPCL(crc, p)
|
|
}
|
|
|
|
func (d *digest) Write(p []byte) (n int, err error) {
|
|
d.crc = d.update(d.crc, p)
|
|
return len(p), nil
|
|
}
|
|
|
|
// Convenience functions
|
|
|
|
func Sum32(data []byte) uint32 {
|
|
crc32 := New()
|
|
crc32.Reset()
|
|
crc32.Write(data)
|
|
return crc32.Sum32()
|
|
}
|
|
|
|
func Sum(reader io.Reader) (uint32, error) {
|
|
h := New()
|
|
var err error
|
|
for err == nil {
|
|
length := 0
|
|
byteBuffer := make([]byte, 1024*1024)
|
|
length, err = reader.Read(byteBuffer)
|
|
byteBuffer = byteBuffer[0:length]
|
|
h.Write(byteBuffer)
|
|
}
|
|
if err != io.EOF {
|
|
return 0, err
|
|
}
|
|
return h.Sum32(), nil
|
|
}
|