var util = require("util"),
stream = require("stream"),
constants = require("./constants");
// TODO: clear up specs on returning false from a write and emitting a drain event.
// Does this mean if I return false from a write, I should ignore any write requests between that false return and the drain event?
var WritableStreamBuffer = module.exports = function(opts) {
var that = this;
stream.Stream.call(this);
opts = opts || {};
var initialSize = opts.initialSize || constants.DEFAULT_INITIAL_SIZE;
var incrementAmount = opts.incrementAmount || constants.DEFAULT_INCREMENT_AMOUNT;
var buffer = new Buffer(initialSize);
var size = 0;
this.writable = true;
this.readable = false;
this.size = function() {
return size;
};
this.maxSize = function() {
return buffer.length;
};
this.getContents = function(length) {
if(!size) return false;
var data = new Buffer(Math.min(length || size, size));
buffer.copy(data, 0, 0, data.length);
Iif(data.length < size)
buffer.copy(buffer, 0, data.length);
size -= data.length;
return data;
};
this.getContentsAsString = function(encoding, length) {
if(!size) return false;
var data = buffer.toString(encoding || "utf8", 0, Math.min(length || size, size));
var dataLength = Buffer.byteLength(data);
if(dataLength < size)
buffer.copy(buffer, 0, dataLength);
size -= dataLength;
return data;
};
var increaseBufferIfNecessary = function(incomingDataSize) {
if((buffer.length - size) < incomingDataSize) {
var factor = Math.ceil((incomingDataSize - (buffer.length - size)) / incrementAmount);
var newBuffer = new Buffer(buffer.length + (incrementAmount * factor));
buffer.copy(newBuffer, 0, 0, size);
buffer = newBuffer;
}
};
this.write = function(data, encoding, callback) {
if(!that.writable) return;
if(Buffer.isBuffer(data)) {
increaseBufferIfNecessary(data.length);
data.copy(buffer, size, 0);
size += data.length;
}
else {
data = data + "";
increaseBufferIfNecessary(Buffer.byteLength(data));
buffer.write(data, size, encoding || "utf8");
size += Buffer.byteLength(data);
}
Iif(typeof callback === "function") { callback() ;}
};
this.end = function() {
var args = Array.prototype.slice.apply(arguments);
Eif(args.length) that.write.apply(that, args);
that.emit('finish');
that.destroy();
};
this.destroySoon = this.destroy = function() {
that.writable = false;
that.emit("close");
};
};
util.inherits(WritableStreamBuffer, stream.Stream);
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