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Utility classes for doing mmap operations

There is a newer version: 1.0.52-3042601

package com.indeed.util.mmap;

import com.google.common.io.ByteStreams;
import org.apache.log4j.Logger;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * @author jplaisance
 */
public final class LoadIndeedMMap {
    private static final Logger log = Logger.getLogger(LoadIndeedMMap.class);

    private static boolean loaded = false;

    public static synchronized void loadLibrary() {
        if (!loaded) {
            try {
                final String osName = System.getProperty("os.name");
                final String arch = System.getProperty("os.arch");
                final String extension = getLibraryType(osName);
                final String resourcePath = "/native/" + osName + "-" + arch + "/libindeedmmap." + extension + ".1.0.1";
                final InputStream is = MMapBuffer.class.getResourceAsStream(resourcePath);
                if (is == null) {
                    throw new FileNotFoundException("unable to find libindeedmmap." + extension + ".1.0.1 at resource path "+resourcePath);
                }
                final File tempFile = File.createTempFile("libindeedmmap", "." + extension);
                final OutputStream os = new FileOutputStream(tempFile);
                ByteStreams.copy(is, os);
                os.close();
                is.close();
                System.load(tempFile.getAbsolutePath());
                // noinspection ResultOfMethodCallIgnored
                tempFile.delete();
            } catch (Throwable e) {
                log.warn("unable to load libindeedmmap using class loader, looking in java.library.path", e);
                System.loadLibrary("indeedmmap"); // if this fails it throws UnsatisfiedLinkError
            }
            loaded = true;
        }
    }

    //i only tested linux, the others are here just in case. i got them from http://lopica.sourceforge.net/os.html
    static String getLibraryType(String os) {
        if (os.startsWith("Linux")) {
            return "so";
        }
        if (os.startsWith("FreeBSD")) {
            return "so";
        }
        if (os.startsWith("Mac OS X")) {
            return "dylib";
        }
        if (os.startsWith("Windows")) {
            return "dll";
        }
        throw new IllegalArgumentException();
    }
}