CharDevice.java

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package com.buglabs.bug.jni.common;

/**
 * Access files from Java and allow ioctls on device nodes.  This class is meant to be used with
 * Linux device nodes.
 * 
 * @author aroman
 *
 */
public class CharDevice {

	protected int fd;

	static {
		System.loadLibrary("Common");
	}

	public int getFileDescriptor() {
		return fd;
	}

	/**
	 * Open a file.
	 * @param file
	 * @param mode Refer to FCNTL_H class for constants to be passed in.
	 * @return negative value on failure.
	 */
	public native int open(String file, int mode);

	/**
	 * @return a full line from the file.
	 */
	public native String getline();

	/**
	 * @return a byte as int from the file.
	 */
	public native int read();

	/**
	 * @param b
	 * @return number of bytes read.
	 */
	public int read(byte[] b) {
		return readBytes(b);
	}

	/**
	 * There's a bug somewhere (gcc, libc, dlopen, or jvm) where overloaded
	 * functions don't map well through jni. Therefore, the function overloading
	 * is at the java layer and renamed the native method to readBytes
	 */
	private native int readBytes(byte[] b);

	/**
	 * @param offset
	 * @param whence
	 * @return
	 */
	public native long lseek(long offset, int whence);

	public native long write(byte[] buf, long count);

	/**
	 * @param request
	 * @return
	 */
	public native int ioctl(int request);

	/**
	 * @return
	 */
	public native int close();
}