distribution/vendor/github.com/stevvooe/resumable/sha512/sha512.go

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// 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 sha512 implements the SHA384 and SHA512 hash algorithms as defined
// in FIPS 180-2.
package sha512
import (
"crypto"
"hash"
)
func init() {
crypto.RegisterHash(crypto.SHA384, New384)
crypto.RegisterHash(crypto.SHA512, New)
}
// The size of a SHA512 checksum in bytes.
const Size = 64
// The size of a SHA384 checksum in bytes.
const Size384 = 48
// The blocksize of SHA512 and SHA384 in bytes.
const BlockSize = 128
const (
chunk = 128
init0 = 0x6a09e667f3bcc908
init1 = 0xbb67ae8584caa73b
init2 = 0x3c6ef372fe94f82b
init3 = 0xa54ff53a5f1d36f1
init4 = 0x510e527fade682d1
init5 = 0x9b05688c2b3e6c1f
init6 = 0x1f83d9abfb41bd6b
init7 = 0x5be0cd19137e2179
init0_384 = 0xcbbb9d5dc1059ed8
init1_384 = 0x629a292a367cd507
init2_384 = 0x9159015a3070dd17
init3_384 = 0x152fecd8f70e5939
init4_384 = 0x67332667ffc00b31
init5_384 = 0x8eb44a8768581511
init6_384 = 0xdb0c2e0d64f98fa7
init7_384 = 0x47b5481dbefa4fa4
)
// digest represents the partial evaluation of a checksum.
type digest struct {
h [8]uint64
x [chunk]byte
nx int
len uint64
is384 bool // mark if this digest is SHA-384
}
func (d *digest) Reset() {
if !d.is384 {
d.h[0] = init0
d.h[1] = init1
d.h[2] = init2
d.h[3] = init3
d.h[4] = init4
d.h[5] = init5
d.h[6] = init6
d.h[7] = init7
} else {
d.h[0] = init0_384
d.h[1] = init1_384
d.h[2] = init2_384
d.h[3] = init3_384
d.h[4] = init4_384
d.h[5] = init5_384
d.h[6] = init6_384
d.h[7] = init7_384
}
d.nx = 0
d.len = 0
}
// New returns a new hash.Hash computing the SHA512 checksum.
func New() hash.Hash {
d := new(digest)
d.Reset()
return d
}
// New384 returns a new hash.Hash computing the SHA384 checksum.
func New384() hash.Hash {
d := new(digest)
d.is384 = true
d.Reset()
return d
}
func (d *digest) Size() int {
if !d.is384 {
return Size
}
return Size384
}
func (d *digest) BlockSize() int { return BlockSize }
func (d *digest) Write(p []byte) (nn int, err error) {
nn = len(p)
d.len += uint64(nn)
if d.nx > 0 {
n := copy(d.x[d.nx:], p)
d.nx += n
if d.nx == chunk {
block(d, d.x[:])
d.nx = 0
}
p = p[n:]
}
if len(p) >= chunk {
n := len(p) &^ (chunk - 1)
block(d, p[:n])
p = p[n:]
}
if len(p) > 0 {
d.nx = copy(d.x[:], p)
}
return
}
func (d0 *digest) Sum(in []byte) []byte {
// Make a copy of d0 so that caller can keep writing and summing.
d := new(digest)
*d = *d0
hash := d.checkSum()
if d.is384 {
return append(in, hash[:Size384]...)
}
return append(in, hash[:]...)
}
func (d *digest) checkSum() [Size]byte {
// Padding. Add a 1 bit and 0 bits until 112 bytes mod 128.
len := d.len
var tmp [128]byte
tmp[0] = 0x80
if len%128 < 112 {
d.Write(tmp[0 : 112-len%128])
} else {
d.Write(tmp[0 : 128+112-len%128])
}
// Length in bits.
len <<= 3
for i := uint(0); i < 16; i++ {
tmp[i] = byte(len >> (120 - 8*i))
}
d.Write(tmp[0:16])
if d.nx != 0 {
panic("d.nx != 0")
}
h := d.h[:]
if d.is384 {
h = d.h[:6]
}
var digest [Size]byte
for i, s := range h {
digest[i*8] = byte(s >> 56)
digest[i*8+1] = byte(s >> 48)
digest[i*8+2] = byte(s >> 40)
digest[i*8+3] = byte(s >> 32)
digest[i*8+4] = byte(s >> 24)
digest[i*8+5] = byte(s >> 16)
digest[i*8+6] = byte(s >> 8)
digest[i*8+7] = byte(s)
}
return digest
}
// Sum512 returns the SHA512 checksum of the data.
func Sum512(data []byte) [Size]byte {
var d digest
d.Reset()
d.Write(data)
return d.checkSum()
}
// Sum384 returns the SHA384 checksum of the data.
func Sum384(data []byte) (sum384 [Size384]byte) {
var d digest
d.is384 = true
d.Reset()
d.Write(data)
sum := d.checkSum()
copy(sum384[:], sum[:Size384])
return
}