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