public static List <Chunk> CompressIDATs(byte[] cipheredBytes)
{
byte[] compressedBytes = ZlibCompression.Compress(cipheredBytes);
List <Chunk> resultIdats = IDATConverter.SplitToIDATs(compressedBytes).Select(idat => (Chunk)idat).ToList();
return(resultIdats);
}
public void ShouldConcatEmptyList()
{
List <IDAT> idats = new List <IDAT>();
byte[] result = IDATConverter.ConcatToBytes(idats);
Assert.AreEqual(new byte[] { }, result);
}
public static byte[] DecompressIDATs(List <Chunk> chunks)
{
List <IDAT> idats = chunks.Where(IsIDAT).Select(chunk => (IDAT)chunk).ToList();
byte[] bytes = IDATConverter.ConcatToBytes(idats);
byte[] decompressedBytes = ZlibCompression.Decompress(bytes);
return(decompressedBytes);
}
public void ShouldSplitToOneIDAT()
{
byte[] bytes = { 1, 3, 5 };
List <IDAT> result = IDATConverter.SplitToIDATs(bytes);
Assert.AreEqual(1, result.Count);
Assert.AreEqual(bytes, result[0].Data);
}
public void ShouldConcatOneIDAT()
{
IDAT idat = new IDAT(new byte[] { 1, 5, 7 }, 0);
List <IDAT> idats = new List <IDAT> {
idat
};
byte[] result = IDATConverter.ConcatToBytes(idats);
Assert.AreEqual(new byte[] { 1, 5, 7 }, result);
}
public void ShouldSplitToThreeIDATsWithOneShorter()
{
byte[] bytes = CreateByteRange(0, short.MaxValue * 2 + 1);
List <IDAT> result = IDATConverter.SplitToIDATs(bytes);
Assert.AreEqual(3, result.Count);
byte[] expectedFirstChunkData = CreateByteRange(0, short.MaxValue);
byte[] expectedSecondChunkData = CreateByteRange(short.MaxValue, short.MaxValue);
byte[] expectedThirdChunkData = CreateByteRange(short.MaxValue * 2, 1);
Assert.AreEqual(expectedFirstChunkData, result[0].Data);
Assert.AreEqual(expectedSecondChunkData, result[1].Data);
Assert.AreEqual(expectedThirdChunkData, result[2].Data);
}
public void ShouldConcatFourIDATs()
{
List <IDAT> idats = new List <IDAT>
{
new IDAT(new byte[] { 1, 5, 7 }, 0),
new IDAT(new byte[] { 4 }, 0),
new IDAT(new byte[] { }, 0),
new IDAT(new byte[] { 2, 5 }, 0)
};
byte[] result = IDATConverter.ConcatToBytes(idats);
Assert.AreEqual(new byte[] { 1, 5, 7, 4, 2, 5 }, result);
}
public void ShouldConcatAndThenSplitImage()
{
string filePath = @"../../../Data/lena.png";
List <Chunk> chunks = PNGFile.Read(filePath);
List <Chunk> parsedChunks = ChunkParser.Parse(chunks);
int firstIdatIndex = parsedChunks.TakeWhile(chunk => !IsIDAT(chunk)).Count();
List <IDAT> idats = parsedChunks.Where(IsIDAT).Select(chunk => (IDAT)chunk).ToList();
byte[] bytes = IDATConverter.ConcatToBytes(idats);
List <Chunk> resultIdats = IDATConverter.SplitToIDATs(bytes).Select(idat => (Chunk)idat).ToList();
List <Chunk> resultChunks = parsedChunks.Where(chunk => !IsIDAT(chunk)).ToList();
resultChunks.InsertRange(firstIdatIndex, resultIdats);
PNGFile.Write(@"../../../Data/lenaConverted.png", resultChunks);
}
