110 lines
2.2 KiB
JavaScript
110 lines
2.2 KiB
JavaScript
'use strict';
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var Buffer = require('safe-buffer').Buffer;
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var toBuffer = require('./to-buffer');
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var Transform = require('readable-stream').Transform;
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var inherits = require('inherits');
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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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if (this._finalized) {
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throw new Error('Digest already called');
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}
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var dataBuffer = toBuffer(data, encoding); // asserts correct input type
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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 + dataBuffer.length - offset >= this._blockSize) {
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for (var i = this._blockOffset; i < this._blockSize;) {
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block[i] = dataBuffer[offset];
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i += 1;
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offset += 1;
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}
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this._update();
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this._blockOffset = 0;
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}
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while (offset < dataBuffer.length) {
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block[this._blockOffset] = dataBuffer[offset];
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this._blockOffset += 1;
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offset += 1;
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}
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// update length
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for (var j = 0, carry = dataBuffer.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) {
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this._length[j] -= 0x0100000000 * carry;
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}
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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) {
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throw new Error('Digest already called');
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}
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this._finalized = true;
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var digest = this._digest();
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if (encoding !== undefined) {
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digest = digest.toString(encoding);
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}
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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) {
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this._length[i] = 0;
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}
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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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