com.github.luben.zstd.util.Native Maven / Gradle / Ivy

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JNI bindings for Zstd native library that provides fast and high compression lossless algorithm for Java and all JVM languages.
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package com.github.luben.zstd.util;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.UnsatisfiedLinkError;

public enum Native {
    ;

    private static final String libnameShort = "zstd-jni";
    private static final String libname = "lib" + libnameShort;
    private static final String errorMsg = "Unsupported OS/arch, cannot find " +
        resourceName() + " or load " + libnameShort + " from system libraries. Please " +
        "try building from source the jar or providing " + libname + " in you system.";

    private static String osName() {
        String os = System.getProperty("os.name").toLowerCase().replace(' ', '_');
        if (os.startsWith("win")){
            return "win";
        } else if (os.startsWith("mac")) {
            return "darwin";
        } else {
            return os;
        }
    }

    private static String osArch() {
        return System.getProperty("os.arch");
    }

    private static String libExtension() {
        if (osName().contains("os_x") || osName().contains("darwin")) {
            return "dylib";
         } else if (osName().contains("win")) {
            return "dll";
        } else {
            return "so";
        }
    }

    private static String resourceName() {
        return "/" + osName() + "/" + osArch() + "/" + libname + "." + libExtension();
    }

    private static boolean loaded = false;

    public static synchronized boolean isLoaded() {
        return loaded;
    }

    private static UnsatisfiedLinkError linkError(UnsatisfiedLinkError e) {
        UnsatisfiedLinkError err = new UnsatisfiedLinkError(e.getMessage() + "\n" + errorMsg);
        err.setStackTrace(e.getStackTrace());
        return err;
    }

    public static synchronized void load() {
        if (loaded) {
            return;
        }

        String resourceName = resourceName();
        InputStream is = Native.class.getResourceAsStream(resourceName);
        if (is == null) {
            // fall-back to loading the zstd-jni from the system library path
            try {
                System.loadLibrary(libnameShort);
                loaded = true;
                return;
            } catch (UnsatisfiedLinkError e) {
                throw linkError(e);
            }
        }
        File tempLib;
        try {
            tempLib = File.createTempFile(libname, "." + libExtension());
            // copy to tempLib
            FileOutputStream out = new FileOutputStream(tempLib);
            try {
                byte[] buf = new byte[4096];
                while (true) {
                    int read = is.read(buf);
                    if (read == -1) {
                        break;
                    }
                    out.write(buf, 0, read);
                }
                try {
                    out.close();
                    out = null;
                } catch (IOException e) {
                    // ignore
                }
                try {
                    System.load(tempLib.getAbsolutePath());
                } catch (UnsatisfiedLinkError e) {
                    // fall-back to loading the zstd-jni from the system library path
                    try {
                        System.loadLibrary(libnameShort);
                    } catch (UnsatisfiedLinkError e1) {
                        throw linkError(e1);
                    }
                }
                loaded = true;
            } finally {
                try {
                    if (out != null) {
                        out.close();
                    }
                } catch (IOException e) {
                  // ignore
                }
                if (tempLib != null && tempLib.exists()) {
                    if (!loaded) {
                        tempLib.delete();
                    } else {
                        // try to delete on exit, does it work on Windows?
                        tempLib.deleteOnExit();
                    }
                }
            }
        } catch (IOException e) {
            throw new ExceptionInInitializerError("Cannot unpack " + libname);
        }
    }
}