ImageSharp/tests/ImageSharp.Tests/Formats/Tiff/Compression/PackBitsTiffCompressionTests.cs

// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using SixLabors.ImageSharp.Formats.Tiff.Compression.Compressors;
using SixLabors.ImageSharp.Formats.Tiff.Compression.Decompressors;
using SixLabors.ImageSharp.IO;
using SixLabors.ImageSharp.Memory;

namespace SixLabors.ImageSharp.Tests.Formats.Tiff.Compression;

[Trait("Format", "Tiff")]
public class PackBitsTiffCompressionTests
{
    [Theory]
    [InlineData(new byte[] { }, new byte[] { })]
    [InlineData(new byte[] { 0x00, 0x2A }, new byte[] { 0x2A })] // Read one byte
    [InlineData(new byte[] { 0x01, 0x15, 0x32 }, new byte[] { 0x15, 0x32 })] // Read two bytes
    [InlineData(new byte[] { 0xFF, 0x2A }, new byte[] { 0x2A, 0x2A })] // Repeat two bytes
    [InlineData(new byte[] { 0xFE, 0x2A }, new byte[] { 0x2A, 0x2A, 0x2A })] // Repeat three bytes
    [InlineData(new byte[] { 0x80 }, new byte[] { })] // Read a 'No operation' byte
    [InlineData(new byte[] { 0x01, 0x15, 0x32, 0x80, 0xFF, 0xA2 }, new byte[] { 0x15, 0x32, 0xA2, 0xA2 })] // Read two bytes, nop, repeat two bytes
    [InlineData(new byte[] { 0xFE, 0xAA, 0x02, 0x80, 0x00, 0x2A, 0xFD, 0xAA, 0x03, 0x80, 0x00, 0x2A, 0x22, 0xF7, 0xAA }, new byte[] { 0xAA, 0xAA, 0xAA, 0x80, 0x00, 0x2A, 0xAA, 0xAA, 0xAA, 0xAA, 0x80, 0x00, 0x2A, 0x22, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA })] // Apple PackBits sample
    public void Decompress_ReadsData(byte[] inputData, byte[] expectedResult)
    {
        using MemoryStream memoryStream = new(inputData);
        using BufferedReadStream stream = new(Configuration.Default, memoryStream);
        byte[] buffer = new byte[expectedResult.Length];

        using PackBitsTiffCompression decompressor = new(MemoryAllocator.Create(), default, default);
        decompressor.Decompress(stream, 0, (uint)inputData.Length, 1, buffer, default);

        Assert.Equal(expectedResult, buffer);
    }

    [Theory]
    [InlineData(new byte[] { 0xAA, 0xAA, 0xAA, 0x80, 0x00, 0x2A, 0xAA, 0xAA, 0xAA, 0xAA, 0x80, 0x00, 0x2A, 0x22, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA }, new byte[] { 0xFE, 0xAA, 0x02, 0x80, 0x00, 0x2A, 0xFD, 0xAA, 0x03, 0x80, 0x00, 0x2A, 0x22, 0xF7, 0xAA })] // Apple PackBits sample
    public void Compress_Works(byte[] inputData, byte[] expectedResult)
    {
        // arrange
        Span<byte> input = inputData.AsSpan();
        byte[] compressed = new byte[expectedResult.Length];

        // act
        PackBitsWriter.PackBits(input, compressed);

        // assert
        Assert.Equal(expectedResult, compressed);
    }
}