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try iconv = require 'iconv-lite'
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class DecodeStream
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constructor: (@buffer) ->
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@pos = 0
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@length = @buffer.length
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@TYPES =
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UInt8: 1
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UInt16: 2
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UInt24: 3
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UInt32: 4
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Int8: 1
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Int16: 2
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Int24: 3
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Int32: 4
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Float: 4
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Double: 8
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for key of Buffer.prototype when key.slice(0, 4) is 'read'
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do (key) =>
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bytes = @TYPES[key.replace(/read|[BL]E/g, '')]
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this::[key] = ->
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ret = @buffer[key](@pos)
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@pos += bytes
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return ret
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readString: (length, encoding = 'ascii') ->
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switch encoding
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when 'utf16le', 'ucs2', 'utf8', 'ascii'
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return @buffer.toString(encoding, @pos, @pos += length)
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when 'utf16be'
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buf = new Buffer(@readBuffer(length))
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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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return buf.toString('utf16le')
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else
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buf = @readBuffer length
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if iconv
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try
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return iconv.decode(buf, encoding)
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return buf
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readBuffer: (length) ->
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|
|
return @buffer.slice(@pos, @pos += length)
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|
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readUInt24BE: ->
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|
|
return (@readUInt16BE() << 8) + @readUInt8()
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|
readUInt24LE: ->
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|
|
return @readUInt16LE() + (@readUInt8() << 16)
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|
readInt24BE: ->
|
|
|
return (@readInt16BE() << 8) + @readUInt8()
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|
|
|
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readInt24LE: ->
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|
|
return @readUInt16LE() + (@readInt8() << 16)
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|
|
|
|
module.exports = DecodeStream
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|
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|
