mirror of
https://github.com/go-gitea/gitea
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292 lines
7.3 KiB
Go
Vendored
292 lines
7.3 KiB
Go
Vendored
// Copyright 2016 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.
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// Package blake2b implements the BLAKE2b hash algorithm defined by RFC 7693
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// and the extendable output function (XOF) BLAKE2Xb.
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//
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// BLAKE2b is optimized for 64-bit platforms—including NEON-enabled ARMs—and
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// produces digests of any size between 1 and 64 bytes.
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// For a detailed specification of BLAKE2b see https://blake2.net/blake2.pdf
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// and for BLAKE2Xb see https://blake2.net/blake2x.pdf
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//
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// If you aren't sure which function you need, use BLAKE2b (Sum512 or New512).
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// If you need a secret-key MAC (message authentication code), use the New512
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// function with a non-nil key.
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//
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// BLAKE2X is a construction to compute hash values larger than 64 bytes. It
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// can produce hash values between 0 and 4 GiB.
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package blake2b
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import (
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"encoding/binary"
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"errors"
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"hash"
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)
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const (
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// The blocksize of BLAKE2b in bytes.
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BlockSize = 128
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// The hash size of BLAKE2b-512 in bytes.
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Size = 64
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// The hash size of BLAKE2b-384 in bytes.
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Size384 = 48
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// The hash size of BLAKE2b-256 in bytes.
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Size256 = 32
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)
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var (
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useAVX2 bool
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useAVX bool
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useSSE4 bool
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)
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var (
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errKeySize = errors.New("blake2b: invalid key size")
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errHashSize = errors.New("blake2b: invalid hash size")
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)
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var iv = [8]uint64{
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0x6a09e667f3bcc908, 0xbb67ae8584caa73b, 0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1,
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0x510e527fade682d1, 0x9b05688c2b3e6c1f, 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179,
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}
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// Sum512 returns the BLAKE2b-512 checksum of the data.
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func Sum512(data []byte) [Size]byte {
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var sum [Size]byte
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checkSum(&sum, Size, data)
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return sum
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}
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// Sum384 returns the BLAKE2b-384 checksum of the data.
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func Sum384(data []byte) [Size384]byte {
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var sum [Size]byte
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var sum384 [Size384]byte
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checkSum(&sum, Size384, data)
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copy(sum384[:], sum[:Size384])
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return sum384
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}
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// Sum256 returns the BLAKE2b-256 checksum of the data.
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func Sum256(data []byte) [Size256]byte {
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var sum [Size]byte
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var sum256 [Size256]byte
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checkSum(&sum, Size256, data)
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copy(sum256[:], sum[:Size256])
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return sum256
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}
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// New512 returns a new hash.Hash computing the BLAKE2b-512 checksum. A non-nil
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// key turns the hash into a MAC. The key must be between zero and 64 bytes long.
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func New512(key []byte) (hash.Hash, error) { return newDigest(Size, key) }
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// New384 returns a new hash.Hash computing the BLAKE2b-384 checksum. A non-nil
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// key turns the hash into a MAC. The key must be between zero and 64 bytes long.
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func New384(key []byte) (hash.Hash, error) { return newDigest(Size384, key) }
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// New256 returns a new hash.Hash computing the BLAKE2b-256 checksum. A non-nil
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// key turns the hash into a MAC. The key must be between zero and 64 bytes long.
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func New256(key []byte) (hash.Hash, error) { return newDigest(Size256, key) }
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// New returns a new hash.Hash computing the BLAKE2b checksum with a custom length.
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// A non-nil key turns the hash into a MAC. The key must be between zero and 64 bytes long.
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// The hash size can be a value between 1 and 64 but it is highly recommended to use
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// values equal or greater than:
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// - 32 if BLAKE2b is used as a hash function (The key is zero bytes long).
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// - 16 if BLAKE2b is used as a MAC function (The key is at least 16 bytes long).
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// When the key is nil, the returned hash.Hash implements BinaryMarshaler
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// and BinaryUnmarshaler for state (de)serialization as documented by hash.Hash.
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func New(size int, key []byte) (hash.Hash, error) { return newDigest(size, key) }
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func newDigest(hashSize int, key []byte) (*digest, error) {
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if hashSize < 1 || hashSize > Size {
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return nil, errHashSize
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}
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if len(key) > Size {
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return nil, errKeySize
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}
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d := &digest{
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size: hashSize,
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keyLen: len(key),
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}
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copy(d.key[:], key)
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d.Reset()
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return d, nil
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}
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func checkSum(sum *[Size]byte, hashSize int, data []byte) {
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h := iv
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h[0] ^= uint64(hashSize) | (1 << 16) | (1 << 24)
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var c [2]uint64
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if length := len(data); length > BlockSize {
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n := length &^ (BlockSize - 1)
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if length == n {
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n -= BlockSize
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}
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hashBlocks(&h, &c, 0, data[:n])
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data = data[n:]
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}
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var block [BlockSize]byte
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offset := copy(block[:], data)
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remaining := uint64(BlockSize - offset)
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if c[0] < remaining {
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c[1]--
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}
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c[0] -= remaining
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hashBlocks(&h, &c, 0xFFFFFFFFFFFFFFFF, block[:])
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for i, v := range h[:(hashSize+7)/8] {
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binary.LittleEndian.PutUint64(sum[8*i:], v)
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}
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}
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type digest struct {
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h [8]uint64
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c [2]uint64
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size int
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block [BlockSize]byte
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offset int
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key [BlockSize]byte
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keyLen int
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}
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const (
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magic = "b2b"
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marshaledSize = len(magic) + 8*8 + 2*8 + 1 + BlockSize + 1
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)
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func (d *digest) MarshalBinary() ([]byte, error) {
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if d.keyLen != 0 {
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return nil, errors.New("crypto/blake2b: cannot marshal MACs")
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}
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b := make([]byte, 0, marshaledSize)
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b = append(b, magic...)
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for i := 0; i < 8; i++ {
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b = appendUint64(b, d.h[i])
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}
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b = appendUint64(b, d.c[0])
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b = appendUint64(b, d.c[1])
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// Maximum value for size is 64
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b = append(b, byte(d.size))
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b = append(b, d.block[:]...)
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b = append(b, byte(d.offset))
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return b, nil
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}
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func (d *digest) UnmarshalBinary(b []byte) error {
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if len(b) < len(magic) || string(b[:len(magic)]) != magic {
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return errors.New("crypto/blake2b: invalid hash state identifier")
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}
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if len(b) != marshaledSize {
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return errors.New("crypto/blake2b: invalid hash state size")
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}
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b = b[len(magic):]
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for i := 0; i < 8; i++ {
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b, d.h[i] = consumeUint64(b)
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}
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b, d.c[0] = consumeUint64(b)
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b, d.c[1] = consumeUint64(b)
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d.size = int(b[0])
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b = b[1:]
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copy(d.block[:], b[:BlockSize])
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b = b[BlockSize:]
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d.offset = int(b[0])
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return nil
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}
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func (d *digest) BlockSize() int { return BlockSize }
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func (d *digest) Size() int { return d.size }
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func (d *digest) Reset() {
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d.h = iv
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d.h[0] ^= uint64(d.size) | (uint64(d.keyLen) << 8) | (1 << 16) | (1 << 24)
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d.offset, d.c[0], d.c[1] = 0, 0, 0
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if d.keyLen > 0 {
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d.block = d.key
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d.offset = BlockSize
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}
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}
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func (d *digest) Write(p []byte) (n int, err error) {
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n = len(p)
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if d.offset > 0 {
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remaining := BlockSize - d.offset
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if n <= remaining {
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d.offset += copy(d.block[d.offset:], p)
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return
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}
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copy(d.block[d.offset:], p[:remaining])
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hashBlocks(&d.h, &d.c, 0, d.block[:])
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d.offset = 0
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p = p[remaining:]
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}
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if length := len(p); length > BlockSize {
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nn := length &^ (BlockSize - 1)
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if length == nn {
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nn -= BlockSize
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}
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hashBlocks(&d.h, &d.c, 0, p[:nn])
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p = p[nn:]
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}
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if len(p) > 0 {
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d.offset += copy(d.block[:], p)
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}
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return
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}
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func (d *digest) Sum(sum []byte) []byte {
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var hash [Size]byte
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d.finalize(&hash)
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return append(sum, hash[:d.size]...)
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}
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func (d *digest) finalize(hash *[Size]byte) {
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var block [BlockSize]byte
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copy(block[:], d.block[:d.offset])
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remaining := uint64(BlockSize - d.offset)
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c := d.c
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if c[0] < remaining {
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c[1]--
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}
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c[0] -= remaining
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h := d.h
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hashBlocks(&h, &c, 0xFFFFFFFFFFFFFFFF, block[:])
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for i, v := range h {
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binary.LittleEndian.PutUint64(hash[8*i:], v)
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}
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}
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func appendUint64(b []byte, x uint64) []byte {
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var a [8]byte
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binary.BigEndian.PutUint64(a[:], x)
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return append(b, a[:]...)
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}
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func appendUint32(b []byte, x uint32) []byte {
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var a [4]byte
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binary.BigEndian.PutUint32(a[:], x)
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return append(b, a[:]...)
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}
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func consumeUint64(b []byte) ([]byte, uint64) {
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x := binary.BigEndian.Uint64(b)
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return b[8:], x
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}
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func consumeUint32(b []byte) ([]byte, uint32) {
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x := binary.BigEndian.Uint32(b)
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return b[4:], x
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}
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