You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
85 lines
1.9 KiB
85 lines
1.9 KiB
1 week ago
|
'use strict';
|
||
|
|
|
||
|
|
var Buffer = require('safe-buffer').Buffer;
|
||
|
|
var toBuffer = require('to-buffer');
|
||
|
|
|
||
|
|
// prototype class for hash functions
|
||
|
|
function Hash(blockSize, finalSize) {
|
||
|
|
this._block = Buffer.alloc(blockSize);
|
||
|
|
this._finalSize = finalSize;
|
||
|
|
this._blockSize = blockSize;
|
||
|
|
this._len = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
Hash.prototype.update = function (data, enc) {
|
||
|
|
/* eslint no-param-reassign: 0 */
|
||
|
|
data = toBuffer(data, enc || 'utf8');
|
||
|
|
|
||
|
|
var block = this._block;
|
||
|
|
var blockSize = this._blockSize;
|
||
|
|
var length = data.length;
|
||
|
|
var accum = this._len;
|
||
|
|
|
||
|
|
for (var offset = 0; offset < length;) {
|
||
|
|
var assigned = accum % blockSize;
|
||
|
|
var remainder = Math.min(length - offset, blockSize - assigned);
|
||
|
|
|
||
|
|
for (var i = 0; i < remainder; i++) {
|
||
|
|
block[assigned + i] = data[offset + i];
|
||
|
|
}
|
||
|
|
|
||
|
|
accum += remainder;
|
||
|
|
offset += remainder;
|
||
|
|
|
||
|
|
if ((accum % blockSize) === 0) {
|
||
|
|
this._update(block);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
this._len += length;
|
||
|
|
return this;
|
||
|
|
};
|
||
|
|
|
||
|
|
Hash.prototype.digest = function (enc) {
|
||
|
|
var rem = this._len % this._blockSize;
|
||
|
|
|
||
|
|
this._block[rem] = 0x80;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* zero (rem + 1) trailing bits, where (rem + 1) is the smallest
|
||
|
|
* non-negative solution to the equation (length + 1 + (rem + 1)) === finalSize mod blockSize
|
||
|
|
*/
|
||
|
|
this._block.fill(0, rem + 1);
|
||
|
|
|
||
|
|
if (rem >= this._finalSize) {
|
||
|
|
this._update(this._block);
|
||
|
|
this._block.fill(0);
|
||
|
|
}
|
||
|
|
|
||
|
|
var bits = this._len * 8;
|
||
|
|
|
||
|
|
// uint32
|
||
|
|
if (bits <= 0xffffffff) {
|
||
|
|
this._block.writeUInt32BE(bits, this._blockSize - 4);
|
||
|
|
|
||
|
|
// uint64
|
||
|
|
} else {
|
||
|
|
var lowBits = (bits & 0xffffffff) >>> 0;
|
||
|
|
var highBits = (bits - lowBits) / 0x100000000;
|
||
|
|
|
||
|
|
this._block.writeUInt32BE(highBits, this._blockSize - 8);
|
||
|
|
this._block.writeUInt32BE(lowBits, this._blockSize - 4);
|
||
|
|
}
|
||
|
|
|
||
|
|
this._update(this._block);
|
||
|
|
var hash = this._hash();
|
||
|
|
|
||
|
|
return enc ? hash.toString(enc) : hash;
|
||
|
|
};
|
||
|
|
|
||
|
|
Hash.prototype._update = function () {
|
||
|
|
throw new Error('_update must be implemented by subclass');
|
||
|
|
};
|
||
|
|
|
||
|
|
module.exports = Hash;
|