// Example to load and open one file stored inside a CPK archive using Cpk.Net

using Cpk.Net;

const string CpkPath = "...";
const string VirtualFilePath = "..."; // Virtualized/relative file path within CPK archive

var cpk = new CpkArchive(CpkPath);
await cpk.LoadAsync();
await using var stream = cpk.Open(VirtualFilePath, out uint size, out bool isCompressed);
...

// Example to load and upack all files stored inside a CPK archive using Cpk.Net

using Cpk.Net;

const string CpkPath = "...";
const string OutputFolderPath = "...";

var cpk = new CpkArchive(CpkPath);
await cpk.LoadAsync(loadIntoMemory: true);
var rootNodes = await cpk.GetRootEntriesAsync();

Unpack(rootNodes, OutputFolderPath);

void Unpack(IList<CpkEntry> nodes, string rootPath)
{
    foreach (var node in nodes)
    {
        // You need to replace CPK directory separator char with
        // your current system directory separator char.
        // So this code can run anywhere.
        var relativePath = node.VirtualPath.Replace(
            CpkConstants.CpkVirtualDirectorySeparatorChar, Path.DirectorySeparatorChar);

        if (node.IsDirectory)
        {
            new DirectoryInfo(rootPath + relativePath).Create();
            Unpack(node.Children, rootPath);
        }
        else
        {
            using var readStream = cpk.Open(node.VirtualPath, out var size, out var isCompressed);
            using var writeStream = new FileStream(rootPath + relativePath, FileMode.Create, FileAccess.Write);
            CopyStream(readStream, writeStream, (int)size, isCompressed ? size : 32768);
            Console.WriteLine($"{node.VirtualPath} unpacked.");
        }
    }
}

static void CopyStream(Stream input, Stream output, int length, uint bufferSize)
{
    byte[] buffer = new byte[bufferSize];
    int read;
    while ((read = input.Read(buffer, 0, Math.Min(buffer.Length, length))) > 0)
    {
        output.Write(buffer, 0, read);
        length -= read;
    }
}