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chunkemitter.js
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chunkemitter.js
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'use strict';
var util = require('util');
var EventEmitter = require('events').EventEmitter;
function ChunkEmitter (buffer_size) {
EventEmitter.call(this);
this.buffer_size = parseInt(buffer_size) || (64 * 1024);
this.buf = null;
this.pos = 0;
this.bufs = [];
this.bufs_size = 0;
}
util.inherits(ChunkEmitter, EventEmitter);
if (!Buffer.concat) {
var buf;
Buffer.concat = function (list, length) {
if (!Array.isArray(list)) {
throw new Error('Usage: Buffer.concat(list, [length])');
}
if (list.length === 0) {
return new Buffer(0);
}
else if (list.length === 1) {
return list[0];
}
if (typeof length !== 'number') {
length = 0;
for (let i = 0; i < list.length; i++) {
buf = list[i];
length += buf.length;
}
}
var buffer = new Buffer(length);
var pos = 0;
for (let i = 0; i < list.length; i++) {
buf = list[i];
buf.copy(buffer, pos);
pos += buf.length;
}
return buffer;
};
}
ChunkEmitter.prototype.fill = function (input) {
if (typeof input === 'string') {
input = new Buffer(input);
}
// Optimization: don't allocate a new buffer until
// the input we've had so far is bigger than our
// buffer size.
if (!this.buf) {
// We haven't allocated a buffer yet
this.bufs.push(input);
this.bufs_size += input.length;
if ((input.length + this.bufs_size) > this.buffer_size) {
this.buf = new Buffer(this.buffer_size);
var in_new = Buffer.concat(this.bufs, this.bufs_size);
input = in_new;
// Reset
this.bufs = [];
this.bufs_size = 0;
}
else {
return;
}
}
while (input.length > 0) {
var remaining = this.buffer_size - this.pos;
if (remaining === 0) {
this.emit('data', this.buf); //.slice(0));
this.buf = new Buffer(this.buffer_size);
this.pos = 0;
remaining = this.buffer_size;
}
var to_write = ((remaining > input.length) ? input.length : remaining);
input.copy(this.buf, this.pos, 0, to_write);
this.pos += to_write;
input = input.slice(to_write);
}
};
ChunkEmitter.prototype.end = function (cb) {
var emitted = false;
if (this.bufs_size > 0) {
this.emit('data', Buffer.concat(this.bufs, this.bufs_size));
emitted = true;
}
else if (this.pos > 0) {
this.emit('data', this.buf.slice(0, this.pos));
emitted = true;
}
// Reset
this.buf = null;
this.pos = 0;
this.bufs = [];
this.bufs_size = 0;
if (cb && typeof cb === 'function') cb();
return emitted;
};
module.exports = ChunkEmitter;