170 lines
3.1 KiB
Go
170 lines
3.1 KiB
Go
// Copyright 2009 The Go Authors. 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 of
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// Golang project:
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// https://github.com/golang/go/blob/master/LICENSE
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// Using this part of Minio codebase under the license
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// Apache License Version 2.0 with modifications
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// Package sha1 implements the SHA1 hash algorithm as defined in RFC 3174.
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package sha1
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import (
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"hash"
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"io"
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"github.com/minio/minio/pkg/cpu"
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)
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// The size of a SHA1 checksum in bytes.
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const Size = 20
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// The blocksize of SHA1 in bytes.
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const BlockSize = 64
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const (
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chunk = 64
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init0 = 0x67452301
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init1 = 0xEFCDAB89
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init2 = 0x98BADCFE
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init3 = 0x10325476
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init4 = 0xC3D2E1F0
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)
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// digest represents the partial evaluation of a checksum.
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type digest struct {
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h [5]uint32
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x [chunk]byte
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nx int
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len uint64
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}
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// Reset digest
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func (d *digest) Reset() {
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d.h[0] = init0
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d.h[1] = init1
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d.h[2] = init2
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d.h[3] = init3
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d.h[4] = init4
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d.nx = 0
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d.len = 0
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}
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// New returns a new hash.Hash computing the SHA1 checksum.
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func New() hash.Hash {
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d := new(digest)
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d.Reset()
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return d
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}
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func block(dig *digest, p []byte) {
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switch true {
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case cpu.HasAVX2() == true:
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blockAVX2(dig, p)
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case cpu.HasSSE41() == true:
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blockSSE3(dig, p)
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default:
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blockGeneric(dig, p)
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}
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}
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// Return output size
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func (d *digest) Size() int { return Size }
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// Return checksum blocksize
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func (d *digest) BlockSize() int { return BlockSize }
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// Write to digest
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func (d *digest) Write(p []byte) (nn int, err error) {
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nn = len(p)
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d.len += uint64(nn)
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if d.nx > 0 {
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n := copy(d.x[d.nx:], p)
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d.nx += n
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if d.nx == chunk {
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block(d, d.x[:])
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d.nx = 0
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}
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p = p[n:]
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}
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if len(p) >= chunk {
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n := len(p) &^ (chunk - 1)
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block(d, p[:n])
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p = p[n:]
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}
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if len(p) > 0 {
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d.nx = copy(d.x[:], p)
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}
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return
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}
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// Return checksum bytes
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func (d *digest) Sum(in []byte) []byte {
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// Make a copy of d0 so that caller can keep writing and summing.
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d0 := *d
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hash := d0.checkSum()
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return append(in, hash[:]...)
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}
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// Intermediate checksum function
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func (d *digest) checkSum() [Size]byte {
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len := d.len
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// Padding. Add a 1 bit and 0 bits until 56 bytes mod 64.
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var tmp [64]byte
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tmp[0] = 0x80
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if len%64 < 56 {
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d.Write(tmp[0 : 56-len%64])
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} else {
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d.Write(tmp[0 : 64+56-len%64])
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}
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// Length in bits.
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len <<= 3
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for i := uint(0); i < 8; i++ {
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tmp[i] = byte(len >> (56 - 8*i))
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}
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d.Write(tmp[0:8])
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if d.nx != 0 {
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panic("d.nx != 0")
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}
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var digest [Size]byte
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for i, s := range d.h {
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digest[i*4] = byte(s >> 24)
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digest[i*4+1] = byte(s >> 16)
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digest[i*4+2] = byte(s >> 8)
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digest[i*4+3] = byte(s)
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}
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return digest
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}
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/// Convenience functions
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// Sum1 - single caller sha1 helper
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func Sum1(data []byte) [Size]byte {
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var d digest
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d.Reset()
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d.Write(data)
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return d.checkSum()
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}
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// Sum - io.Reader based streaming sha1 helper
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func Sum(reader io.Reader) ([]byte, error) {
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h := New()
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var err error
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for err == nil {
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length := 0
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byteBuffer := make([]byte, 1024*1024)
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length, err = reader.Read(byteBuffer)
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byteBuffer = byteBuffer[0:length]
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h.Write(byteBuffer)
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}
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if err != io.EOF {
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return nil, err
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}
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return h.Sum(nil), nil
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}
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