[deliverable/tracecompass.git] / org.eclipse.linuxtools.tmf.core / src / org / eclipse / linuxtools / tmf / core / 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.core.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
/**\r
 * A class to mitigate the Java I/O inefficiency of RandomAccessFile.\r
 *\r
 * @version 1.0\r
 * @author Patrick Tasse\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
    /**\r
     * Constructor using the default buffer size\r
     *\r
     * @param name\r
     *            File path. This is passed as-is to the RandomeAccessFile's\r
     *            constructor.\r
     * @param mode\r
     *            File open mode ("r", "rw", etc.). This is passed as-is to\r
     *            RandomAccessFile's constructor.\r
     * @throws IOException\r
     *             If the file was not found or couldn't be opened with the\r
     *             request permissions\r
     */\r
	public BufferedRandomAccessFile(String name, String mode) throws IOException {\r
		this(name, mode, DEFAULT_BUF_SIZE);\r
	}\r
\r
    /**\r
     * Constructor using the default buffer size\r
     *\r
     * @param file\r
     *            File object. This is passed as-is to the RandomeAccessFile's\r
     *            constructor.\r
     * @param mode\r
     *            File open mode ("r", "rw", etc.). This is passed as-is to\r
     *            RandomAccessFile's constructor.\r
     * @throws IOException\r
     *             If the file was not found or couldn't be opened with the\r
     *             request permissions\r
     */\r
	public BufferedRandomAccessFile(File file, String mode) throws IOException {\r
		this(file, mode, DEFAULT_BUF_SIZE);\r
	}\r
\r
    /**\r
     * Standard constructor.\r
     *\r
     * @param name\r
     *            File path. This is passed as-is to the RandomeAccessFile's\r
     *            constructor.\r
     * @param mode\r
     *            File open mode ("r", "rw", etc.). This is passed as-is to\r
     *            RandomAccessFile's constructor.\r
     * @param bufsize\r
     *            Buffer size to use, in bytes\r
     * @throws IOException\r
     *             If the file was not found or couldn't be opened with the\r
     *             request permissions\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
    /**\r
     * Standard constructor.\r
     *\r
     * @param file\r
     *            File object. This is passed as-is to the RandomeAccessFile's\r
     *            constructor.\r
     * @param mode\r
     *            File open mode ("r", "rw", etc.). This is passed as-is to\r
     *            RandomAccessFile's constructor.\r
     * @param bufsize\r
     *            Buffer size to use, in bytes\r
     * @throws IOException\r
     *             If the file was not found or couldn't be opened with the\r
     *             request permissions\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
		}\r
        return buffer[buf_pos++];\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
    /**\r
     * Read the next line from the buffer (ie, until the next '\n'). The bytes\r
     * are interpreted as UTF-8 characters.\r
     *\r
     * @return The String that was read\r
     * @throws IOException\r
     *             If we failed reading the file\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
Commit	Line	Data
9520695b FC	1	/*******************************************************************************\r
9520695b FC	2	* Copyright (c) 2010 Ericsson\r
9b749023	3	*\r
9520695b FC	4	* All rights reserved. This program and the accompanying materials are\r
	5	* made available under the terms of the Eclipse Public License v1.0 which\r
	6	* accompanies this distribution, and is available at\r
	7	* http://www.eclipse.org/legal/epl-v10.html\r
9b749023	8	*\r
9520695b FC	9	* Contributors:\r
	10	* Patrick Tasse - Initial API and implementation, based on article by Nick Zhang\r
	11	* (http://www.javaworld.com/javatips/jw-javatip26.html)\r
	12	******************************************************************************/\r
	13	\r
6c13869b	14	package org.eclipse.linuxtools.tmf.core.io;\r
9520695b FC	15	\r
	16	import java.io.File;\r
	17	import java.io.IOException;\r
	18	import java.io.RandomAccessFile;\r
	19	import java.nio.charset.Charset;\r
	20	\r
d09f973b	21	/**\r
9b749023 AM	22	* A class to mitigate the Java I/O inefficiency of RandomAccessFile.\r
9b749023 AM	23	*\r
d09f973b FC	24	* @version 1.0\r
	25	* @author Patrick Tasse\r
	26	*/\r
9520695b FC	27	public class BufferedRandomAccessFile extends RandomAccessFile {\r
	28	\r
	29	private static final int DEFAULT_BUF_SIZE = 8192;\r
	30	private static final Charset CHARSET_UTF8 = Charset.forName("UTF-8"); //$NON-NLS-1$\r
9b749023	31	\r
9520695b FC	32	final int BUF_SIZE;\r
	33	byte buffer[];\r
	34	int buf_end = 0;\r
	35	int buf_pos = 0;\r
	36	long real_pos = 0;\r
	37	StringBuilder sb = new StringBuilder();\r
9b749023	38	\r
063f0d27 AM	39	/**\r
	40	* Constructor using the default buffer size\r
	41	*\r
	42	* @param name\r
	43	* File path. This is passed as-is to the RandomeAccessFile's\r
	44	* constructor.\r
	45	* @param mode\r
	46	* File open mode ("r", "rw", etc.). This is passed as-is to\r
	47	* RandomAccessFile's constructor.\r
	48	* @throws IOException\r
	49	* If the file was not found or couldn't be opened with the\r
	50	* request permissions\r
	51	*/\r
9520695b FC	52	public BufferedRandomAccessFile(String name, String mode) throws IOException {\r
	53	this(name, mode, DEFAULT_BUF_SIZE);\r
	54	}\r
9b749023	55	\r
063f0d27 AM	56	/**\r
	57	* Constructor using the default buffer size\r
	58	*\r
	59	* @param file\r
	60	* File object. This is passed as-is to the RandomeAccessFile's\r
	61	* constructor.\r
	62	* @param mode\r
	63	* File open mode ("r", "rw", etc.). This is passed as-is to\r
	64	* RandomAccessFile's constructor.\r
	65	* @throws IOException\r
	66	* If the file was not found or couldn't be opened with the\r
	67	* request permissions\r
	68	*/\r
9520695b FC	69	public BufferedRandomAccessFile(File file, String mode) throws IOException {\r
	70	this(file, mode, DEFAULT_BUF_SIZE);\r
	71	}\r
9b749023	72	\r
063f0d27 AM	73	/**\r
	74	* Standard constructor.\r
	75	*\r
	76	* @param name\r
	77	* File path. This is passed as-is to the RandomeAccessFile's\r
	78	* constructor.\r
	79	* @param mode\r
	80	* File open mode ("r", "rw", etc.). This is passed as-is to\r
	81	* RandomAccessFile's constructor.\r
	82	* @param bufsize\r
	83	* Buffer size to use, in bytes\r
	84	* @throws IOException\r
	85	* If the file was not found or couldn't be opened with the\r
	86	* request permissions\r
	87	*/\r
9520695b FC	88	public BufferedRandomAccessFile(String name, String mode, int bufsize) throws IOException {\r
	89	super(name, mode);\r
	90	invalidate();\r
	91	BUF_SIZE = bufsize;\r
	92	buffer = new byte[BUF_SIZE];\r
	93	}\r
	94	\r
063f0d27 AM	95	/**\r
	96	* Standard constructor.\r
	97	*\r
	98	* @param file\r
	99	* File object. This is passed as-is to the RandomeAccessFile's\r
	100	* constructor.\r
	101	* @param mode\r
	102	* File open mode ("r", "rw", etc.). This is passed as-is to\r
	103	* RandomAccessFile's constructor.\r
	104	* @param bufsize\r
	105	* Buffer size to use, in bytes\r
	106	* @throws IOException\r
	107	* If the file was not found or couldn't be opened with the\r
	108	* request permissions\r
	109	*/\r
9520695b FC	110	public BufferedRandomAccessFile(File file, String mode, int bufsize) throws IOException {\r
	111	super(file, mode);\r
	112	invalidate();\r
	113	BUF_SIZE = bufsize;\r
	114	buffer = new byte[BUF_SIZE];\r
	115	}\r
	116	\r
	117	@Override\r
	118	public final int read() throws IOException{\r
	119	if (buf_pos >= buf_end) {\r
	120	if (fillBuffer() < 0) {\r
	121	return -1;\r
	122	}\r
	123	}\r
	124	if (buf_end == 0) {\r
	125	return -1;\r
9520695b	126	}\r
9b749023	127	return buffer[buf_pos++];\r
9520695b	128	}\r
9b749023	129	\r
9520695b FC	130	@Override\r
	131	public int read(byte b[], int off, int len) throws IOException {\r
	132	int leftover = buf_end - buf_pos;\r
	133	if (len <= leftover) {\r
	134	System.arraycopy(buffer, buf_pos, b, off, len);\r
	135	buf_pos += len;\r
	136	return len;\r
	137	}\r
	138	for(int i = 0; i < len; i++) {\r
	139	int c = this.read();\r
	140	if (c != -1) {\r
	141	b[off+i] = (byte) c;\r
	142	} else {\r
	143	return i;\r
	144	}\r
	145	}\r
	146	return len;\r
	147	}\r
9b749023	148	\r
9520695b FC	149	@Override\r
	150	public long getFilePointer() throws IOException{\r
	151	long l = real_pos;\r
	152	return (l - buf_end + buf_pos);\r
	153	}\r
	154	\r
	155	@Override\r
	156	public void seek(long pos) throws IOException {\r
	157	int n = (int) (real_pos - pos);\r
	158	if(n >= 0 && n <= buf_end) {\r
	159	buf_pos = buf_end - n;\r
	160	} else {\r
	161	super.seek(pos);\r
	162	invalidate();\r
	163	}\r
	164	}\r
	165	\r
063f0d27 AM	166	/**\r
	167	* Read the next line from the buffer (ie, until the next '\n'). The bytes\r
	168	* are interpreted as UTF-8 characters.\r
	169	*\r
	170	* @return The String that was read\r
	171	* @throws IOException\r
	172	* If we failed reading the file\r
	173	*/\r
9520695b FC	174	public final String getNextLine() throws IOException {\r
	175	String str = null;\r
	176	if (buf_end - buf_pos <= 0) {\r
	177	if (fillBuffer() < 0) {\r
	178	return null;\r
	179	}\r
	180	}\r
	181	int lineend = -1;\r
	182	for (int i = buf_pos; i < buf_end; i++) {\r
	183	if (buffer[i] == '\n') {\r
	184	lineend = i;\r
	185	break;\r
	186	}\r
	187	}\r
	188	if (lineend < 0) {\r
	189	sb.delete(0, sb.length());\r
	190	int c;\r
	191	while (((c = read()) != -1) && (c != '\n')) {\r
	192	sb.append((char) c);\r
	193	}\r
	194	if ((c == -1) && (sb.length() == 0)) {\r
	195	return null;\r
	196	}\r
	197	if (sb.charAt(sb.length() - 1) == '\r') {\r
	198	sb.deleteCharAt(sb.length() - 1);\r
	199	}\r
	200	return sb.toString();\r
	201	}\r
	202	if (lineend > 0 && buffer[lineend - 1] == '\r' && lineend > buf_pos) {\r
	203	str = new String(buffer, buf_pos, lineend - buf_pos - 1, CHARSET_UTF8);\r
	204	} else {\r
	205	str = new String(buffer, buf_pos, lineend - buf_pos, CHARSET_UTF8);\r
	206	}\r
	207	buf_pos = lineend + 1;\r
	208	return str;\r
	209	}\r
9b749023	210	\r
9520695b FC	211	private int fillBuffer() throws IOException {\r
	212	int n = super.read(buffer, 0, BUF_SIZE);\r
	213	if (n >= 0) {\r
	214	real_pos += n;\r
	215	buf_end = n;\r
	216	buf_pos = 0;\r
	217	}\r
	218	return n;\r
	219	}\r
9b749023	220	\r
9520695b FC	221	private void invalidate() throws IOException {\r
	222	buf_end = 0;\r
	223	buf_pos = 0;\r
	224	real_pos = super.getFilePointer();\r
	225	}\r
	226	}\r