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USAGE.md

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Usage

Initialization

Joveler.Compression.ZLib requires explicit loading of a zlib library.

You must call ZLibInit.GlobalInit() before using Joveler.Compression.ZLib.

Put this snippet in your application's init code:

public static void InitNativeLibrary()
{
    const string x64 = "x64";
    const string x86 = "x86";
    const string armhf = "armhf";
    const string arm64 = "arm64";

    const string dllName = "zlibwapi.dll";
    const string soName = "libz.so";

    string libPath = null;
    if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
    {
        switch (RuntimeInformation.ProcessArchitecture)
        {
            case Architecture.X86:
                libPath = Path.Combine(x86, dllName);
                break;
            case Architecture.X64:
                libPath = Path.Combine(x64, dllName);
                break;
        }
    }
    else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
    {
        switch (RuntimeInformation.ProcessArchitecture)
        {
            case Architecture.X64:
                libPath = Path.Combine(x64, soName);
                break;
            case Architecture.Arm:
                libPath = Path.Combine(armhf, soName);
                break;
            case Architecture.Arm64:
                libPath = Path.Combine(arm64, soName);
                break;
        }
    }

    if (libPath == null)
        throw new PlatformNotSupportedException();

    ZLibInit.GlobalInit(libPath);
}

WARNING: Caller process and callee library must have the same architecture!

Embedded binary

Joveler.Compression.ZLib comes with sets of static binaries of zlib 1.2.11.
They will be copied into the build directory at build time.

Platform Binary Note
Windows x86 $(OutDir)\x86\zlibwpi.dll Compiled without assembly optimization, due to the bug
Windows x64 $(OutDir)\x64\zlibwpi.dll
Linux x64 $(OutDir)\x64\libz.so Compiled in Ubuntu 18.04
Linux armhf $(OutDir)\armhf\libz.so Compiled in Debian 9
Linux arm64 $(OutDir)\arm64\libz.so Compiled in Debian 9

Custom binary

To use custom zlib binary instead, call ZLibInit.GlobalInit() with a path to the custom binary.

NOTES

  • Create an empty file named Joveler.Compression.ZLib.Precompiled.Exclude in project directory to prevent copy of package-embedded binary.
  • Joveler.Compression.ZLib can only recognize zlibwapi.dll (stdcall) , not zlib1.dll (cdecl).
  • Untested on arm64, because .Net Core 2.1 arm64 runtime has an issue.

Cleanup

To unload zlib library explicitly, call ZLibInit.GlobalCleanup().

Compression

DeflateStream

The stream to process a data format conforming RFC 1951.

Its API is similar to System.IO.Compression.DeflateStream.

Ex) Compression

using (FileStream fsOrigin = new FileStream("file_origin.bin", FileMode.Open))
using (FileStream fsComp = new FileStream("test.deflate", FileMode.Create))
using (DeflateStream zs = new DeflateStream(fsComp, ZLibMode.Compress, ZLibCompLevel.Default))
{
    fsOrigin.CopyTo(zs);
}

Joveler.Compression.ZLib.CompressionLevel has more option compared to System.IO.Compression.CompressionLevel:

public enum ZLibCompLevel : int
{
    Default = -1,
    NoCompression = 0,
    BestSpeed = 1,
    BestCompression = 9,
    Level0 = 0,
    Level1 = 1,
    Level2 = 2,
    Level3 = 3,
    Level4 = 4,
    Level5 = 5,
    Level6 = 6,
    Level7 = 7,
    Level8 = 8,
    Level9 = 9,
}

Ex) Decompression

using (FileStream fsComp = new FileStream("test.deflate", FileMode.Create))
using (FileStream fsDecomp = new FileStream("file_decomp.bin", FileMode.Open))
using (DeflateStream zs = new DeflateStream(fsComp, ZLibMode.Decompress))
{
    zs.CopyTo(fsDecomp);
}

ZLibStream

A stream to process a data format conforming RFC 1950.

Same usage with DeflateStream.

GZipStream

A stream to process a data format conforming RFC 1952.

Same usage with DeflateStream.

DeflateCompressor

A helper class for DeflateStream.

Ex) DeflateCompressor.Compress(Stream stream)

using (FileStream fsOrigin = new FileStream("file_origin.bin", FileMode.Open))
using (MemoryStream msComp = DeflateCompressor.Compress(fsOrigin))
{
    // write msComp to file, or send through network, etc
}

Ex) DeflateCompressor.Decompress(byte[] buffer)

byte[] input = new byte[] { 0x73, 0x74, 0x72, 0x76, 0x71, 0x75, 0x03, 0x00 };
byte[] decompBytes = DeflateCompressor.Decompress(input);
string decompText = Encoding.UTF8.GetString(decompBytes);
Console.WriteLine(decompText); // "ABCDEF"

ZLibCompressor

A helper class for ZLibStream.

Same usage with DeflateCompressor.

GZipCompressor

A helper class for GZipStream.

Same usage with DeflateCompressor.

Checksum

NOTE: To use checksum calculation, you MUST USE zlibwapi.dll.

Adler32Checksum

A class to compute the adler32 checksum.

Use Append() methods to compute checksum.
Use Checksum property to get checksum value.

Ex) Append(Stream stream)

using (FileStream fs = new FileStream("read.txt", FileMode.Open))
{
    Adler32Checksum adler = new Adler32Checksum();
    adler.Append(fs);
    Console.WriteLine("0x" + adler.Checksum.ToString("X8"));
}

Ex) Append(byte[] buffer), Append(byte[] buffer, int offset, int count)

Adler32Checksum adler = new Adler32Checksum();
byte[] bin = Encoding.UTF8.GetBytes("ABCDEF");

adler.Append(bin);
Console.WriteLine("0x" + adler.Checksum.ToString("X8")); // 0x057E0196

adler.Append(bin, 2, 3);
Console.WriteLine("0x" + adler.Checksum.ToString("X8")); // 0x0BD60262

Static wrapper methods named Adler32Checksum.Adler32() behave just like zlib's adler32() function.

Example of static wrapper methods:

byte[] bin = Encoding.UTF8.GetBytes("ABCDEF");

// Call Adler32() without checksum to use initial state.
uint checksum = Adler32Checksum.Adler32(bin);
Console.WriteLine("0x" + checksum.ToString("X8")); // 0x057E0196

// Call Adler32() with checksum to set as current state.
checksum = Adler32Checksum.Adler32(checksum, bin, 2, 3);
Console.WriteLine("0x" + checksum.ToString("X8")); // 0x0BD60262

// Stream can be passed to Adler32() as well as byte
using (MemoryStream ms = new MemoryStream(bin))
{
    checksum = Adler32Checksum.Adler32(ms);
    Console.WriteLine("0x" + checksum.ToString("X8")); // 0x057E0196
}

Crc32Checksum

Same usage with Adler32Checksum.

To use static wrapper methods, call Crc32Checksum.Crc32() instead of Adler32Checksum.Adler32().

Adler32Stream

A stream designed to compute adler32 checksum on-the-fly.

Ex) Reading from AdlerStream

using (FileStream fs = new FileStream("read.bin", FileMode.Open))
using (Adler32Stream adler = new Adler32Stream(fs))
{
    byte[] buffer = new byte[256];
    adler.Read(buffer, 0, 256);
    Console.WriteLine("0x" + adler.Checksum.ToString("X8"));

    adler.Read(buffer, 0, 128);
    Console.WriteLine("0x" + adler.Checksum.ToString("X8"));
}

Ex) Writing to AdlerStream

using (FileStream fs = new FileStream("write.bin", FileMode.Create))
using (Adler32Stream adler = new Adler32Stream(fs))
{
    byte[] bin;

    bin = new byte[] { 0x01, 0x02, 0x03 };
    adler.Write(bin, 0, bin.Length);
    Console.WriteLine("0x" + adler.Checksum.ToString("X8")); // 0x000D0007

    bin = new byte[] { 0x04, 0x05, 0x06 };
    adler.Write(bin, 0, bin.Length);
    Console.WriteLine("0x" + adler.Checksum.ToString("X8")); // 0x003E0016
}

Crc32Stream

Same usage with Adler32Stream.