|
1 | | -var Buffer = require('safe-buffer').Buffer |
| 1 | +'use strict'; |
| 2 | + |
| 3 | +var Buffer = require('safe-buffer').Buffer; |
2 | 4 |
|
3 | 5 | // prototype class for hash functions |
4 | | -function Hash (blockSize, finalSize) { |
5 | | - this._block = Buffer.alloc(blockSize) |
6 | | - this._finalSize = finalSize |
7 | | - this._blockSize = blockSize |
8 | | - this._len = 0 |
| 6 | +function Hash(blockSize, finalSize) { |
| 7 | + this._block = Buffer.alloc(blockSize); |
| 8 | + this._finalSize = finalSize; |
| 9 | + this._blockSize = blockSize; |
| 10 | + this._len = 0; |
9 | 11 | } |
10 | 12 |
|
11 | 13 | Hash.prototype.update = function (data, enc) { |
12 | | - if (typeof data === 'string') { |
13 | | - enc = enc || 'utf8' |
14 | | - data = Buffer.from(data, enc) |
15 | | - } |
16 | | - |
17 | | - var block = this._block |
18 | | - var blockSize = this._blockSize |
19 | | - var length = data.length |
20 | | - var accum = this._len |
21 | | - |
22 | | - for (var offset = 0; offset < length;) { |
23 | | - var assigned = accum % blockSize |
24 | | - var remainder = Math.min(length - offset, blockSize - assigned) |
25 | | - |
26 | | - for (var i = 0; i < remainder; i++) { |
27 | | - block[assigned + i] = data[offset + i] |
28 | | - } |
29 | | - |
30 | | - accum += remainder |
31 | | - offset += remainder |
32 | | - |
33 | | - if ((accum % blockSize) === 0) { |
34 | | - this._update(block) |
35 | | - } |
36 | | - } |
37 | | - |
38 | | - this._len += length |
39 | | - return this |
40 | | -} |
| 14 | + /* eslint no-param-reassign: 0 */ |
| 15 | + if (typeof data === 'string') { |
| 16 | + enc = enc || 'utf8'; |
| 17 | + data = Buffer.from(data, enc); |
| 18 | + } |
| 19 | + |
| 20 | + var block = this._block; |
| 21 | + var blockSize = this._blockSize; |
| 22 | + var length = data.length; |
| 23 | + var accum = this._len; |
| 24 | + |
| 25 | + for (var offset = 0; offset < length;) { |
| 26 | + var assigned = accum % blockSize; |
| 27 | + var remainder = Math.min(length - offset, blockSize - assigned); |
| 28 | + |
| 29 | + for (var i = 0; i < remainder; i++) { |
| 30 | + block[assigned + i] = data[offset + i]; |
| 31 | + } |
| 32 | + |
| 33 | + accum += remainder; |
| 34 | + offset += remainder; |
| 35 | + |
| 36 | + if ((accum % blockSize) === 0) { |
| 37 | + this._update(block); |
| 38 | + } |
| 39 | + } |
| 40 | + |
| 41 | + this._len += length; |
| 42 | + return this; |
| 43 | +}; |
41 | 44 |
|
42 | 45 | Hash.prototype.digest = function (enc) { |
43 | | - var rem = this._len % this._blockSize |
| 46 | + var rem = this._len % this._blockSize; |
44 | 47 |
|
45 | | - this._block[rem] = 0x80 |
| 48 | + this._block[rem] = 0x80; |
46 | 49 |
|
47 | | - // zero (rem + 1) trailing bits, where (rem + 1) is the smallest |
48 | | - // non-negative solution to the equation (length + 1 + (rem + 1)) === finalSize mod blockSize |
49 | | - this._block.fill(0, rem + 1) |
| 50 | + /* |
| 51 | + * zero (rem + 1) trailing bits, where (rem + 1) is the smallest |
| 52 | + * non-negative solution to the equation (length + 1 + (rem + 1)) === finalSize mod blockSize |
| 53 | + */ |
| 54 | + this._block.fill(0, rem + 1); |
50 | 55 |
|
51 | | - if (rem >= this._finalSize) { |
52 | | - this._update(this._block) |
53 | | - this._block.fill(0) |
54 | | - } |
| 56 | + if (rem >= this._finalSize) { |
| 57 | + this._update(this._block); |
| 58 | + this._block.fill(0); |
| 59 | + } |
55 | 60 |
|
56 | | - var bits = this._len * 8 |
| 61 | + var bits = this._len * 8; |
57 | 62 |
|
58 | | - // uint32 |
59 | | - if (bits <= 0xffffffff) { |
60 | | - this._block.writeUInt32BE(bits, this._blockSize - 4) |
| 63 | + // uint32 |
| 64 | + if (bits <= 0xffffffff) { |
| 65 | + this._block.writeUInt32BE(bits, this._blockSize - 4); |
61 | 66 |
|
62 | | - // uint64 |
63 | | - } else { |
64 | | - var lowBits = (bits & 0xffffffff) >>> 0 |
65 | | - var highBits = (bits - lowBits) / 0x100000000 |
| 67 | + // uint64 |
| 68 | + } else { |
| 69 | + var lowBits = (bits & 0xffffffff) >>> 0; |
| 70 | + var highBits = (bits - lowBits) / 0x100000000; |
66 | 71 |
|
67 | | - this._block.writeUInt32BE(highBits, this._blockSize - 8) |
68 | | - this._block.writeUInt32BE(lowBits, this._blockSize - 4) |
69 | | - } |
| 72 | + this._block.writeUInt32BE(highBits, this._blockSize - 8); |
| 73 | + this._block.writeUInt32BE(lowBits, this._blockSize - 4); |
| 74 | + } |
70 | 75 |
|
71 | | - this._update(this._block) |
72 | | - var hash = this._hash() |
| 76 | + this._update(this._block); |
| 77 | + var hash = this._hash(); |
73 | 78 |
|
74 | | - return enc ? hash.toString(enc) : hash |
75 | | -} |
| 79 | + return enc ? hash.toString(enc) : hash; |
| 80 | +}; |
76 | 81 |
|
77 | 82 | Hash.prototype._update = function () { |
78 | | - throw new Error('_update must be implemented by subclass') |
79 | | -} |
| 83 | + throw new Error('_update must be implemented by subclass'); |
| 84 | +}; |
80 | 85 |
|
81 | | -module.exports = Hash |
| 86 | +module.exports = Hash; |
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