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stream = require 'stream'
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DecodeStream = require './DecodeStream'
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try iconv = require 'iconv-lite'
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class EncodeStream extends stream.Readable
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constructor: (bufferSize = 65536) ->
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super
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@buffer = new Buffer(bufferSize)
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@bufferOffset = 0
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@pos = 0
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for key of Buffer.prototype when key.slice(0, 5) is 'write'
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do (key) =>
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bytes = +DecodeStream.TYPES[key.replace(/write|[BL]E/g, '')]
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EncodeStream::[key] = (value) ->
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@ensure bytes
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@buffer[key](value, @bufferOffset)
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@bufferOffset += bytes
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@pos += bytes
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_read: ->
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# do nothing, required by node
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ensure: (bytes) ->
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if @bufferOffset + bytes > @buffer.length
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@flush()
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flush: ->
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if @bufferOffset > 0
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@push new Buffer @buffer.slice(0, @bufferOffset)
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@bufferOffset = 0
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writeBuffer: (buffer) ->
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@flush()
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@push buffer
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@pos += buffer.length
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writeString: (string, encoding = 'ascii') ->
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switch encoding
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when 'utf16le', 'ucs2', 'utf8', 'ascii'
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@writeBuffer new Buffer(string, encoding)
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when 'utf16be'
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buf = new Buffer(string, 'utf16le')
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# swap the bytes
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for i in [0...buf.length - 1] by 2
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byte = buf[i]
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buf[i] = buf[i + 1]
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buf[i + 1] = byte
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@writeBuffer buf
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else
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if iconv
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@writeBuffer iconv.encode(string, encoding)
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else
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throw new Error 'Install iconv-lite to enable additional string encodings.'
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writeUInt24BE: (val) ->
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@ensure 3
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@buffer[@bufferOffset++] = val >>> 16 & 0xff
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@buffer[@bufferOffset++] = val >>> 8 & 0xff
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@buffer[@bufferOffset++] = val & 0xff
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@pos += 3
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writeUInt24LE: (val) ->
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@ensure 3
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@buffer[@bufferOffset++] = val & 0xff
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@buffer[@bufferOffset++] = val >>> 8 & 0xff
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@buffer[@bufferOffset++] = val >>> 16 & 0xff
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@pos += 3
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writeInt24BE: (val) ->
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if val >= 0
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@writeUInt24BE val
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else
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@writeUInt24BE val + 0xffffff + 1
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writeInt24LE: (val) ->
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if val >= 0
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@writeUInt24LE val
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else
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@writeUInt24LE val + 0xffffff + 1
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fill: (val, length) ->
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if length < @buffer.length
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@ensure length
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@buffer.fill(val, @bufferOffset, @bufferOffset + length)
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@bufferOffset += length
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@pos += length
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else
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buf = new Buffer(length)
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buf.fill(val)
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@writeBuffer buf
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end: ->
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@flush()
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@push null
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module.exports = EncodeStream
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