www.aleph1.co.uk Git - yaffs-website/blob - node_modules/stringstream/stringstream.js

   1 var util = require('util')
   2 var Stream = require('stream')
   3 var StringDecoder = require('string_decoder').StringDecoder
   4
   5 module.exports = StringStream
   6 module.exports.AlignedStringDecoder = AlignedStringDecoder
   7
   8 function StringStream(from, to) {
   9   if (!(this instanceof StringStream)) return new StringStream(from, to)
  10
  11   Stream.call(this)
  12
  13   if (from == null) from = 'utf8'
  14
  15   this.readable = this.writable = true
  16   this.paused = false
  17   this.toEncoding = (to == null ? from : to)
  18   this.fromEncoding = (to == null ? '' : from)
  19   this.decoder = new AlignedStringDecoder(this.toEncoding)
  20 }
  21 util.inherits(StringStream, Stream)
  22
  23 StringStream.prototype.write = function(data) {
  24   if (!this.writable) {
  25     var err = new Error('stream not writable')
  26     err.code = 'EPIPE'
  27     this.emit('error', err)
  28     return false
  29   }
  30   if (this.fromEncoding) {
  31     if (Buffer.isBuffer(data)) data = data.toString()
  32     data = new Buffer(data, this.fromEncoding)
  33   }
  34   var string = this.decoder.write(data)
  35   if (string.length) this.emit('data', string)
  36   return !this.paused
  37 }
  38
  39 StringStream.prototype.flush = function() {
  40   if (this.decoder.flush) {
  41     var string = this.decoder.flush()
  42     if (string.length) this.emit('data', string)
  43   }
  44 }
  45
  46 StringStream.prototype.end = function() {
  47   if (!this.writable && !this.readable) return
  48   this.flush()
  49   this.emit('end')
  50   this.writable = this.readable = false
  51   this.destroy()
  52 }
  53
  54 StringStream.prototype.destroy = function() {
  55   this.decoder = null
  56   this.writable = this.readable = false
  57   this.emit('close')
  58 }
  59
  60 StringStream.prototype.pause = function() {
  61   this.paused = true
  62 }
  63
  64 StringStream.prototype.resume = function () {
  65   if (this.paused) this.emit('drain')
  66   this.paused = false
  67 }
  68
  69 function AlignedStringDecoder(encoding) {
  70   StringDecoder.call(this, encoding)
  71
  72   switch (this.encoding) {
  73     case 'base64':
  74       this.write = alignedWrite
  75       this.alignedBuffer = new Buffer(3)
  76       this.alignedBytes = 0
  77       break
  78   }
  79 }
  80 util.inherits(AlignedStringDecoder, StringDecoder)
  81
  82 AlignedStringDecoder.prototype.flush = function() {
  83   if (!this.alignedBuffer || !this.alignedBytes) return ''
  84   var leftover = this.alignedBuffer.toString(this.encoding, 0, this.alignedBytes)
  85   this.alignedBytes = 0
  86   return leftover
  87 }
  88
  89 function alignedWrite(buffer) {
  90   var rem = (this.alignedBytes + buffer.length) % this.alignedBuffer.length
  91   if (!rem && !this.alignedBytes) return buffer.toString(this.encoding)
  92
  93   var returnBuffer = new Buffer(this.alignedBytes + buffer.length - rem)
  94
  95   this.alignedBuffer.copy(returnBuffer, 0, 0, this.alignedBytes)
  96   buffer.copy(returnBuffer, this.alignedBytes, 0, buffer.length - rem)
  97
  98   buffer.copy(this.alignedBuffer, 0, buffer.length - rem, buffer.length)
  99   this.alignedBytes = rem
 100
 101   return returnBuffer.toString(this.encoding)
 102 }