Rename xxx.lttng to xxx.lttng.core

[deliverable/tracecompass.git] / org.eclipse.linuxtools.tmf / src / org / eclipse / linuxtools / tmf / io / BufferedRandomAccessFile.java

/*******************************************************************************\r
 * Copyright (c) 2010 Ericsson\r
 * \r
 * All rights reserved. This program and the accompanying materials are\r
 * made available under the terms of the Eclipse Public License v1.0 which\r
 * accompanies this distribution, and is available at\r
 * http://www.eclipse.org/legal/epl-v10.html\r
 * \r
 * Contributors:\r
 *   Patrick Tasse - Initial API and implementation, based on article by Nick Zhang\r
 *                   (http://www.javaworld.com/javatips/jw-javatip26.html)\r
 ******************************************************************************/\r
\r
package org.eclipse.linuxtools.tmf.io;\r
\r
import java.io.File;\r
import java.io.IOException;\r
import java.io.RandomAccessFile;\r
import java.nio.charset.Charset;\r
\r
public class BufferedRandomAccessFile extends RandomAccessFile {\r
\r
	private static final int DEFAULT_BUF_SIZE = 8192;\r
	private static final Charset CHARSET_UTF8 = Charset.forName("UTF-8"); //$NON-NLS-1$\r
	\r
	final int BUF_SIZE;\r
	byte buffer[];\r
	int buf_end = 0;\r
	int buf_pos = 0;\r
	long real_pos = 0;\r
	StringBuilder sb = new StringBuilder();\r
	\r
	public BufferedRandomAccessFile(String name, String mode) throws IOException {\r
		this(name, mode, DEFAULT_BUF_SIZE);\r
	}\r
	\r
	public BufferedRandomAccessFile(File file, String mode) throws IOException {\r
		this(file, mode, DEFAULT_BUF_SIZE);\r
	}\r
	\r
	public BufferedRandomAccessFile(String name, String mode, int bufsize) throws IOException {\r
	    super(name, mode);\r
	    invalidate();\r
	    BUF_SIZE = bufsize;\r
	    buffer = new byte[BUF_SIZE];\r
    }\r
\r
	public BufferedRandomAccessFile(File file, String mode, int bufsize) throws IOException {\r
	    super(file, mode);\r
	    invalidate();\r
	    BUF_SIZE = bufsize;\r
	    buffer = new byte[BUF_SIZE];\r
    }\r
\r
	@Override\r
    public final int read() throws IOException{\r
		if (buf_pos >= buf_end) {\r
			if (fillBuffer() < 0) {\r
				return -1;\r
			}\r
		}\r
		if (buf_end == 0) {\r
			return -1;\r
		} else {\r
			return buffer[buf_pos++];\r
		}\r
	}\r
	\r
	@Override\r
    public int read(byte b[], int off, int len) throws IOException {\r
		int leftover = buf_end - buf_pos;\r
		if (len <= leftover) {\r
			System.arraycopy(buffer, buf_pos, b, off, len);\r
			buf_pos += len;\r
			return len;\r
		}\r
		for(int i = 0; i < len; i++) {\r
			int c = this.read();\r
			if (c != -1) {\r
				b[off+i] = (byte) c;\r
			} else {\r
				return i;\r
			}\r
		}\r
		return len;\r
	}\r
	\r
	@Override\r
    public long getFilePointer() throws IOException{\r
		long l = real_pos;\r
		return (l - buf_end + buf_pos);\r
	}\r
\r
	@Override\r
    public void seek(long pos) throws IOException {\r
		int n = (int) (real_pos - pos);\r
		if(n >= 0 && n <= buf_end) {\r
			buf_pos = buf_end - n;\r
		} else {\r
			super.seek(pos);\r
			invalidate();\r
		}\r
	}\r
\r
	public final String getNextLine() throws IOException {\r
		String str = null;\r
		if (buf_end - buf_pos <= 0) {\r
			if (fillBuffer() < 0) {\r
				return null;\r
			}\r
		}\r
		int lineend = -1;\r
		for (int i = buf_pos; i < buf_end; i++) {\r
			if (buffer[i] == '\n') {\r
				lineend = i;\r
				break;\r
			}\r
		}\r
		if (lineend < 0) {\r
			sb.delete(0, sb.length());\r
			int c;\r
			while (((c = read()) != -1) && (c != '\n')) {\r
				sb.append((char) c);\r
			}\r
			if ((c == -1) && (sb.length() == 0)) {\r
				return null;\r
			}\r
			if (sb.charAt(sb.length() - 1) == '\r') {\r
				sb.deleteCharAt(sb.length() - 1);\r
			}\r
			return sb.toString();\r
		}\r
		if (lineend > 0 && buffer[lineend - 1] == '\r' && lineend > buf_pos) {\r
			str = new String(buffer, buf_pos, lineend - buf_pos - 1, CHARSET_UTF8);\r
		} else {\r
			str = new String(buffer, buf_pos, lineend - buf_pos, CHARSET_UTF8);\r
		}\r
		buf_pos = lineend + 1;\r
		return str;\r
	}\r
	  \r
	private int fillBuffer() throws IOException {\r
		int n = super.read(buffer, 0, BUF_SIZE);\r
		if (n >= 0) {\r
			real_pos += n;\r
			buf_end = n;\r
			buf_pos = 0;\r
		}\r
		return n;\r
	}\r
	\r
	private void invalidate() throws IOException {\r
		buf_end = 0;\r
		buf_pos = 0;\r
		real_pos = super.getFilePointer();\r
	}\r
}\r