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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.
// This package implements the SHA384 and SHA512 hash algorithms as defined in FIPS 180-2.
package sha512
import (
"hash"
"os"
)
// The size of a SHA512 checksum in bytes.
const Size = 64
// The size of a SHA384 checksum in bytes.
const Size384 = 48
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) Write(p []byte) (nn int, err os.Error) {
nn = len(p)
d.len += uint64(nn)
if d.nx > 0 {
n := len(p)
if n > _Chunk-d.nx {
n = _Chunk - d.nx
}
for i := 0; i < n; i++ {
d.x[d.nx+i] = p[i]
}
d.nx += n
if d.nx == _Chunk {
_Block(d, d.x[0:])
d.nx = 0
}
p = p[n:]
}
n := _Block(d, p)
p = p[n:]
if len(p) > 0 {
d.nx = copy(d.x[:], p)
}
return
}
func (d0 *digest) Sum() []byte {
// Make a copy of d0 so that caller can keep writing and summing.
d := new(digest)
*d = *d0
// 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")
}
p := make([]byte, 64)
j := 0
for _, s := range d.h {
p[j+0] = byte(s >> 56)
p[j+1] = byte(s >> 48)
p[j+2] = byte(s >> 40)
p[j+3] = byte(s >> 32)
p[j+4] = byte(s >> 24)
p[j+5] = byte(s >> 16)
p[j+6] = byte(s >> 8)
p[j+7] = byte(s >> 0)
j += 8
}
if d.is384 {
return p[0:48]
}
return p
}