103 lines
2.7 KiB
JavaScript
103 lines
2.7 KiB
JavaScript
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var util = require('util')
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var Stream = require('stream')
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var StringDecoder = require('string_decoder').StringDecoder
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module.exports = StringStream
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module.exports.AlignedStringDecoder = AlignedStringDecoder
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function StringStream(from, to) {
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if (!(this instanceof StringStream)) return new StringStream(from, to)
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Stream.call(this)
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if (from == null) from = 'utf8'
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this.readable = this.writable = true
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this.paused = false
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this.toEncoding = (to == null ? from : to)
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this.fromEncoding = (to == null ? '' : from)
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this.decoder = new AlignedStringDecoder(this.toEncoding)
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}
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util.inherits(StringStream, Stream)
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StringStream.prototype.write = function(data) {
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if (!this.writable) {
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var err = new Error('stream not writable')
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err.code = 'EPIPE'
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this.emit('error', err)
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return false
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}
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if (this.fromEncoding) {
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if (Buffer.isBuffer(data)) data = data.toString()
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data = new Buffer(data, this.fromEncoding)
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}
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var string = this.decoder.write(data)
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if (string.length) this.emit('data', string)
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return !this.paused
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}
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StringStream.prototype.flush = function() {
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if (this.decoder.flush) {
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var string = this.decoder.flush()
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if (string.length) this.emit('data', string)
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}
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}
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StringStream.prototype.end = function() {
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if (!this.writable && !this.readable) return
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this.flush()
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this.emit('end')
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this.writable = this.readable = false
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this.destroy()
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}
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StringStream.prototype.destroy = function() {
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this.decoder = null
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this.writable = this.readable = false
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this.emit('close')
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}
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StringStream.prototype.pause = function() {
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this.paused = true
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}
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StringStream.prototype.resume = function () {
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if (this.paused) this.emit('drain')
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this.paused = false
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}
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function AlignedStringDecoder(encoding) {
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StringDecoder.call(this, encoding)
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switch (this.encoding) {
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case 'base64':
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this.write = alignedWrite
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this.alignedBuffer = new Buffer(3)
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this.alignedBytes = 0
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break
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}
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}
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util.inherits(AlignedStringDecoder, StringDecoder)
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AlignedStringDecoder.prototype.flush = function() {
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if (!this.alignedBuffer || !this.alignedBytes) return ''
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var leftover = this.alignedBuffer.toString(this.encoding, 0, this.alignedBytes)
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this.alignedBytes = 0
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return leftover
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}
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function alignedWrite(buffer) {
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var rem = (this.alignedBytes + buffer.length) % this.alignedBuffer.length
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if (!rem && !this.alignedBytes) return buffer.toString(this.encoding)
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var returnBuffer = new Buffer(this.alignedBytes + buffer.length - rem)
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this.alignedBuffer.copy(returnBuffer, 0, 0, this.alignedBytes)
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buffer.copy(returnBuffer, this.alignedBytes, 0, buffer.length - rem)
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buffer.copy(this.alignedBuffer, 0, buffer.length - rem, buffer.length)
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this.alignedBytes = rem
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return returnBuffer.toString(this.encoding)
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}
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