RLE Decompress

RLE (Run-length encoding) is a very simple form of lossless data compression in which runs of data (that is, sequences in which the same data value occurs in many consecutive data elements) are stored as a single data value and count, rather than as the original run. This is most useful on data that contains many such runs.

For RLE Compress algorithm click here.

• C#
• VB.Net
• C
• C++

									Public Shared Sub Decompress(input As Byte(), output As Byte(), inputSize As UInteger)
	Dim marker As Byte, symbol As Byte
	Dim i As UInteger, inputPosition As UInteger, outputPosition As UInteger, count As UInteger

	If inputSize < 1 Then
		Return
	End If

	inputPosition = 0
	marker = input(inputPosition)
	inputPosition += 1
	outputPosition = 0

	Do
		symbol = input(inputPosition)
		inputPosition += 1

		If symbol = marker Then
			count = input(inputPosition)
			inputPosition += 1

			If count <= 2 Then
				For i = 0 To count
					output(outputPosition) = marker
					outputPosition += 1
				Next
			Else
				If Convert.ToBoolean(count And &H80) Then
					count = ((count And &H7F) << 8) + input(inputPosition)
					inputPosition += 1
				End If

				symbol = input(inputPosition)
				inputPosition += 1

				For i = 0 To count
					output(outputPosition) = symbol
					outputPosition += 1
				Next
			End If
		Else
			output(outputPosition) = symbol
			outputPosition += 1
		End If
	Loop While inputPosition < inputSize
End Sub
								

Example

									Dim decompressedData As Byte() = New Byte(originalDataSize - 1) {}

Decompress(compressedData, decompressedData, CUInt(compressedDataSize))