randomaccessfile.java

kaffe是一个java虚拟机的源代码。里面包含了一些java例程和标准的java包。

/*
 * Java core library component.
 *
 * Copyright (c) 1997, 1998
 *      Transvirtual Technologies, Inc.  All rights reserved.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file.
 */

package java.io;

import kaffe.util.UTF8;

public class RandomAccessFile implements DataOutput, DataInput {
	private final FileDescriptor fd = new FileDescriptor();

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

public RandomAccessFile(File file, String mode) throws IOException {
	this(file.getPath(), mode);
}

public RandomAccessFile(String name, String mode) throws FileNotFoundException {
	boolean writable;
	if (mode.equalsIgnoreCase("r")) writable=false;
	else if (mode.equalsIgnoreCase("rw")) writable=true;
	else throw new IllegalArgumentException();

	final SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
		sm.checkRead(name);
		if (writable) {
		    sm.checkWrite(name);
		}
	}

	open(name, writable);
}

native public void close() throws IOException;

final public FileDescriptor getFD() throws IOException {
	return fd;
}

native public long getFilePointer() throws IOException;

native public long length() throws IOException;

native private void open(String name, boolean rw);

native public int read() throws IOException;

public int read(byte b[]) throws IOException {
	return read(b, 0, b.length);
}

public int read(byte b[], int off, int len) throws IOException {
	int total = 0;
	while (total < len) {
		final int got = readBytes(b, off + total, len - total);
		if (got == -1) {
			break;
		}
		total += got;
	}
	if (len > 0 && total == 0) {
		return -1;
	}
	return total;
}

final public boolean readBoolean() throws IOException {
	return (readByte()==0);
}

final public byte readByte() throws IOException {
	final int value = read();
	if (value == -1) {
		throw new EOFException();
	}
	return (byte)value;
}

native private int readBytes(byte bytes[], int off, int len);

final public char readChar() throws IOException {
	final int b1=readUnsignedByte();
	final int b2=readUnsignedByte();

	return (char )((b1 << 8) | b2);
}

final public double readDouble() throws IOException {
	return Double.longBitsToDouble(readLong());
}

final public float readFloat() throws IOException {
	return Float.intBitsToFloat(readInt());
}

final public void readFully(byte b[]) throws IOException {
	readFully(b, 0, b.length);
}

final public void readFully(byte b[], int off, int len) throws IOException {
	int got = read(b, off, len);
	if (got != len) {
		throw new EOFException();
	}
}

final public int readInt() throws IOException {
	int b1=readUnsignedByte();
	int b2=readUnsignedByte();
	int b3=readUnsignedByte();
	int b4=readUnsignedByte();

	return (b1 << 24) | (b2 << 16) + (b3 << 8) + b4;
}

final public String readLine() throws IOException {
	final StringBuffer buffer = new StringBuffer();
	int nread = 0;

	while (true) {
		final int data = read();
		final char ch = (char) (data & 0xff);

		if (data == -1)
			break;
		nread++;
		if (ch == '\n')
			break;
		if (ch == '\r') {       // Check for '\r\n'
			final int data2 = read();
			final char ch2 = (char) (data2 & 0xff);

			if (data2 != -1 && ch2 != '\n')
				seek(getFilePointer() - 1);
			break;
		}
		buffer.append(ch);
	}
	return (nread == 0) ? null : buffer.toString();
}

final public long readLong() throws IOException {
	int i1=readInt(); /* b1-4 */
	int i2=readInt(); /* b5-8 */

	return ((long)i1 << 32) + (((long)i2) & 0xffffffffL);
}

final public short readShort() throws IOException {
	int b1=readUnsignedByte();
	int b2=readUnsignedByte();

	return (short)((b1 << 8)|b2);
}

final public String readUTF() throws IOException {
	return UTF8.decode(this, readUnsignedShort());
}

final public int readUnsignedByte() throws IOException {
	return (int)readByte() & 0xFF;
}

final public int readUnsignedShort() throws IOException {
	int b1=readUnsignedByte();
	int b2=readUnsignedByte();

	return (b1 << 8) | b2;
}

native public void seek(long pos) throws IOException;

public int skipBytes(int n) throws IOException {
	long pos = getFilePointer();
	seek(pos+(long)n);
	return n;
}

public void write(byte b[]) throws IOException {
	writeBytes(b, 0, b.length);
}

public void write(byte b[], int off, int len) throws IOException {
	writeBytes(b, off, len);
}

native public void write(int b) throws IOException;

final public void writeBoolean(boolean v) throws IOException {
	if (v) writeByte(1); else writeByte(0);
}

final public void writeByte(int v) throws IOException {
	write(v);
}

final public void writeBytes(String s) throws IOException {
	char[] c = s.toCharArray();
	byte[] b = new byte[c.length];
	for (int pos = 0; pos < c.length; pos++) {
		b[pos] = (byte)(c[pos] & 0xFF);
	}
	write(b, 0, b.length);
}

native private void writeBytes(byte bytes[], int off, int len);

final public void writeChar(int v) throws IOException {
	writeByte((v & 0xFF00) >> 8);
	writeByte((v & 0x00FF));
}

final public void writeChars(String s) throws IOException {
	for (int pos=0; pos<s.length(); pos++) {
		writeChar(s.charAt(pos));
	}
}

final public void writeDouble(double v) throws IOException {
	writeLong(Double.doubleToLongBits(v));
}

final public void writeFloat(float v) throws IOException {
	writeInt(Float.floatToIntBits(v));
}

final public void writeInt(int v) throws IOException {
	byte b[] = new byte[4];
	int i, shift;

	for (i = 0, shift = 24; i < 4; i++, shift -= 8)
		b[i] = (byte)(0xFF & (v >> shift));
	write(b, 0, 4);
}

final public void writeLong(long v) throws IOException {
	int hiInt=(int )(v >> 32);
	int loInt=(int )(v & 0xFFFFFFFF);

	writeInt(hiInt);
	writeInt(loInt);
}

final public void writeShort(int v) throws IOException {
	writeChar(v);
}

final public void writeUTF(String str) throws IOException {
	byte[] data = UTF8.encode(str);
	if (data.length > 0xffff) {
		throw new UTFDataFormatException("String too long");
	}
	synchronized(this) {
		writeShort(data.length);
		write(data, 0, data.length);
	}
}

}