73 lines
1.8 KiB
JavaScript
73 lines
1.8 KiB
JavaScript
'use strict';
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var util = require('util');
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var stream = require('stream');
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var constants = require('./constants');
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var WritableStreamBuffer = module.exports = function(opts) {
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opts = opts || {};
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opts.decodeStrings = true;
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stream.Writable.call(this, opts);
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var initialSize = opts.initialSize || constants.DEFAULT_INITIAL_SIZE;
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var incrementAmount = opts.incrementAmount || constants.DEFAULT_INCREMENT_AMOUNT;
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var buffer = new Buffer(initialSize);
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var size = 0;
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this.size = function() {
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return size;
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};
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this.maxSize = function() {
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return buffer.length;
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};
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this.getContents = function(length) {
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if(!size) return false;
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var data = new Buffer(Math.min(length || size, size));
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buffer.copy(data, 0, 0, data.length);
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if(data.length < size)
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buffer.copy(buffer, 0, data.length);
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size -= data.length;
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return data;
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};
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this.getContentsAsString = function(encoding, length) {
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if(!size) return false;
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var data = buffer.toString(encoding || 'utf8', 0, Math.min(length || size, size));
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var dataLength = Buffer.byteLength(data);
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if(dataLength < size)
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buffer.copy(buffer, 0, dataLength);
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size -= dataLength;
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return data;
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};
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var increaseBufferIfNecessary = function(incomingDataSize) {
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if((buffer.length - size) < incomingDataSize) {
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var factor = Math.ceil((incomingDataSize - (buffer.length - size)) / incrementAmount);
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var newBuffer = new Buffer(buffer.length + (incrementAmount * factor));
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buffer.copy(newBuffer, 0, 0, size);
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buffer = newBuffer;
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}
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};
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this._write = function(chunk, encoding, callback) {
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increaseBufferIfNecessary(chunk.length);
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chunk.copy(buffer, size, 0);
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size += chunk.length;
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callback();
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};
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};
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util.inherits(WritableStreamBuffer, stream.Writable);
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