forked from zhurui/management
96 lines
2.3 KiB
JavaScript
96 lines
2.3 KiB
JavaScript
'use strict'
|
|
var Buffer = require('safe-buffer').Buffer
|
|
var Transform = require('readable-stream').Transform
|
|
var inherits = require('inherits')
|
|
|
|
function throwIfNotStringOrBuffer (val, prefix) {
|
|
if (!Buffer.isBuffer(val) && typeof val !== 'string') {
|
|
throw new TypeError(prefix + ' must be a string or a buffer')
|
|
}
|
|
}
|
|
|
|
function HashBase (blockSize) {
|
|
Transform.call(this)
|
|
|
|
this._block = Buffer.allocUnsafe(blockSize)
|
|
this._blockSize = blockSize
|
|
this._blockOffset = 0
|
|
this._length = [0, 0, 0, 0]
|
|
|
|
this._finalized = false
|
|
}
|
|
|
|
inherits(HashBase, Transform)
|
|
|
|
HashBase.prototype._transform = function (chunk, encoding, callback) {
|
|
var error = null
|
|
try {
|
|
this.update(chunk, encoding)
|
|
} catch (err) {
|
|
error = err
|
|
}
|
|
|
|
callback(error)
|
|
}
|
|
|
|
HashBase.prototype._flush = function (callback) {
|
|
var error = null
|
|
try {
|
|
this.push(this.digest())
|
|
} catch (err) {
|
|
error = err
|
|
}
|
|
|
|
callback(error)
|
|
}
|
|
|
|
HashBase.prototype.update = function (data, encoding) {
|
|
throwIfNotStringOrBuffer(data, 'Data')
|
|
if (this._finalized) throw new Error('Digest already called')
|
|
if (!Buffer.isBuffer(data)) data = Buffer.from(data, encoding)
|
|
|
|
// consume data
|
|
var block = this._block
|
|
var offset = 0
|
|
while (this._blockOffset + data.length - offset >= this._blockSize) {
|
|
for (var i = this._blockOffset; i < this._blockSize;) block[i++] = data[offset++]
|
|
this._update()
|
|
this._blockOffset = 0
|
|
}
|
|
while (offset < data.length) block[this._blockOffset++] = data[offset++]
|
|
|
|
// update length
|
|
for (var j = 0, carry = data.length * 8; carry > 0; ++j) {
|
|
this._length[j] += carry
|
|
carry = (this._length[j] / 0x0100000000) | 0
|
|
if (carry > 0) this._length[j] -= 0x0100000000 * carry
|
|
}
|
|
|
|
return this
|
|
}
|
|
|
|
HashBase.prototype._update = function () {
|
|
throw new Error('_update is not implemented')
|
|
}
|
|
|
|
HashBase.prototype.digest = function (encoding) {
|
|
if (this._finalized) throw new Error('Digest already called')
|
|
this._finalized = true
|
|
|
|
var digest = this._digest()
|
|
if (encoding !== undefined) digest = digest.toString(encoding)
|
|
|
|
// reset state
|
|
this._block.fill(0)
|
|
this._blockOffset = 0
|
|
for (var i = 0; i < 4; ++i) this._length[i] = 0
|
|
|
|
return digest
|
|
}
|
|
|
|
HashBase.prototype._digest = function () {
|
|
throw new Error('_digest is not implemented')
|
|
}
|
|
|
|
module.exports = HashBase
|