com.twelvemonkeys.io.LittleEndianRandomAccessFile Maven / Gradle / Ivy
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name "TwelveMonkeys" nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.io;
import java.io.*;
import java.nio.channels.FileChannel;
/**
* A replacement for {@link java.io.RandomAccessFile} that is capable of reading
* and writing data in little endian byte order.
*
* Warning:
*
* The {@code DataInput} and {@code DataOutput} interfaces
* specifies big endian byte order in their documentation.
* This means that this class is, strictly speaking, not a proper
* implementation. However, I don't see a reason for the these interfaces to
* specify the byte order of their underlying representations.
*
*
* @see com.twelvemonkeys.io.LittleEndianDataInputStream
* @see com.twelvemonkeys.io.LittleEndianDataOutputStream
* @see java.io.RandomAccessFile
* @see java.io.DataInput
* @see java.io.DataOutput
*
* @author Elliotte Rusty Harold
* @author Harald Kuhr
* @author last modified by $Author: haku $
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/io/LittleEndianRandomAccessFile.java#1 $
*/
public class LittleEndianRandomAccessFile implements DataInput, DataOutput {
private RandomAccessFile mFile;
public LittleEndianRandomAccessFile(final String pName, final String pMode) throws FileNotFoundException {
this(FileUtil.resolve(pName), pMode);
}
public LittleEndianRandomAccessFile(final File pFile, final String pMode) throws FileNotFoundException {
mFile = new RandomAccessFile(pFile, pMode);
}
public void close() throws IOException {
mFile.close();
}
public FileChannel getChannel() {
return mFile.getChannel();
}
public FileDescriptor getFD() throws IOException {
return mFile.getFD();
}
public long getFilePointer() throws IOException {
return mFile.getFilePointer();
}
public long length() throws IOException {
return mFile.length();
}
public int read() throws IOException {
return mFile.read();
}
public int read(final byte[] b) throws IOException {
return mFile.read(b);
}
public int read(final byte[] b, final int off, final int len) throws IOException {
return mFile.read(b, off, len);
}
public void readFully(final byte[] b) throws IOException {
mFile.readFully(b);
}
public void readFully(final byte[] b, final int off, final int len) throws IOException {
mFile.readFully(b, off, len);
}
public String readLine() throws IOException {
return mFile.readLine();
}
/**
* Reads a boolean from the underlying input stream by
* reading a single byte. If the byte is zero, false is returned.
* If the byte is positive, true is returned.
*
* @return the boolean value read.
* @throws EOFException if the end of the underlying input stream
* has been reached
* @throws IOException if the underlying stream throws an IOException.
*/
public boolean readBoolean() throws IOException {
int b = mFile.read();
if (b < 0) {
throw new EOFException();
}
return b != 0;
}
/**
* Reads a signed byte from the underlying input stream
* with value between -128 and 127
*
* @return the byte value read.
* @throws EOFException if the end of the underlying input stream
* has been reached
* @throws IOException if the underlying stream throws an IOException.
*/
public byte readByte() throws IOException {
int b = mFile.read();
if (b < 0) {
throw new EOFException();
}
return (byte) b;
}
/**
* Reads an unsigned byte from the underlying
* input stream with value between 0 and 255
*
* @return the byte value read.
* @throws EOFException if the end of the underlying input
* stream has been reached
* @throws IOException if the underlying stream throws an IOException.
*/
public int readUnsignedByte() throws IOException {
int b = mFile.read();
if (b < 0) {
throw new EOFException();
}
return b;
}
/**
* Reads a two byte signed short from the underlying
* input stream in little endian order, low byte first.
*
* @return the short read.
* @throws EOFException if the end of the underlying input stream
* has been reached
* @throws IOException if the underlying stream throws an IOException.
*/
public short readShort() throws IOException {
int byte1 = mFile.read();
int byte2 = mFile.read();
// only need to test last byte read
// if byte1 is -1 so is byte2
if (byte2 < 0) {
throw new EOFException();
}
return (short) (((byte2 << 24) >>> 16) + (byte1 << 24) >>> 24);
}
/**
* Reads a two byte unsigned short from the underlying
* input stream in little endian order, low byte first.
*
* @return the int value of the unsigned short read.
* @throws EOFException if the end of the underlying input stream
* has been reached
* @throws IOException if the underlying stream throws an IOException.
*/
public int readUnsignedShort() throws IOException {
int byte1 = mFile.read();
int byte2 = mFile.read();
if (byte2 < 0) {
throw new EOFException();
}
//return ((byte2 << 24) >> 16) + ((byte1 << 24) >> 24);
return (byte2 << 8) + byte1;
}
/**
* Reads a two byte Unicode char from the underlying
* input stream in little endian order, low byte first.
*
* @return the int value of the unsigned short read.
* @throws EOFException if the end of the underlying input stream
* has been reached
* @throws IOException if the underlying stream throws an IOException.
*/
public char readChar() throws IOException {
int byte1 = mFile.read();
int byte2 = mFile.read();
if (byte2 < 0) {
throw new EOFException();
}
return (char) (((byte2 << 24) >>> 16) + ((byte1 << 24) >>> 24));
}
/**
* Reads a four byte signed int from the underlying
* input stream in little endian order, low byte first.
*
* @return the int read.
* @throws EOFException if the end of the underlying input stream
* has been reached
* @throws IOException if the underlying stream throws an IOException.
*/
public int readInt() throws IOException {
int byte1 = mFile.read();
int byte2 = mFile.read();
int byte3 = mFile.read();
int byte4 = mFile.read();
if (byte4 < 0) {
throw new EOFException();
}
return (byte4 << 24) + ((byte3 << 24) >>> 8)
+ ((byte2 << 24) >>> 16) + ((byte1 << 24) >>> 24);
}
/**
* Reads an eight byte signed int from the underlying
* input stream in little endian order, low byte first.
*
* @return the int read.
* @throws EOFException if the end of the underlying input stream
* has been reached
* @throws IOException if the underlying stream throws an IOException.
*/
public long readLong() throws IOException {
long byte1 = mFile.read();
long byte2 = mFile.read();
long byte3 = mFile.read();
long byte4 = mFile.read();
long byte5 = mFile.read();
long byte6 = mFile.read();
long byte7 = mFile.read();
long byte8 = mFile.read();
if (byte8 < 0) {
throw new EOFException();
}
return (byte8 << 56) + ((byte7 << 56) >>> 8)
+ ((byte6 << 56) >>> 16) + ((byte5 << 56) >>> 24)
+ ((byte4 << 56) >>> 32) + ((byte3 << 56) >>> 40)
+ ((byte2 << 56) >>> 48) + ((byte1 << 56) >>> 56);
}
/**
* Reads a string of no more than 65,535 characters
* from the underlying input stream using UTF-8
* encoding. This method first reads a two byte short
* in big endian order as required by the
* UTF-8 specification. This gives the number of bytes in
* the UTF-8 encoded version of the string.
* Next this many bytes are read and decoded as UTF-8
* encoded characters.
*
* @return the decoded string
* @throws UTFDataFormatException if the string cannot be decoded
* @throws IOException if the underlying stream throws an IOException.
*/
public String readUTF() throws IOException {
int byte1 = mFile.read();
int byte2 = mFile.read();
if (byte2 < 0) {
throw new EOFException();
}
int numbytes = (byte1 << 8) + byte2;
char result[] = new char[numbytes];
int numread = 0;
int numchars = 0;
while (numread < numbytes) {
int c1 = readUnsignedByte();
int c2, c3;
// The first four bits of c1 determine how many bytes are in this char
int test = c1 >> 4;
if (test < 8) { // one byte
numread++;
result[numchars++] = (char) c1;
}
else if (test == 12 || test == 13) { // two bytes
numread += 2;
if (numread > numbytes) {
throw new UTFDataFormatException();
}
c2 = readUnsignedByte();
if ((c2 & 0xC0) != 0x80) {
throw new UTFDataFormatException();
}
result[numchars++] = (char) (((c1 & 0x1F) << 6) | (c2 & 0x3F));
}
else if (test == 14) { // three bytes
numread += 3;
if (numread > numbytes) {
throw new UTFDataFormatException();
}
c2 = readUnsignedByte();
c3 = readUnsignedByte();
if (((c2 & 0xC0) != 0x80) || ((c3 & 0xC0) != 0x80)) {
throw new UTFDataFormatException();
}
result[numchars++] = (char)
(((c1 & 0x0F) << 12) | ((c2 & 0x3F) << 6) | (c3 & 0x3F));
}
else { // malformed
throw new UTFDataFormatException();
}
} // end while
return new String(result, 0, numchars);
}
/**
* @return the next eight bytes of this input stream, interpreted as a
* little endian double.
* @throws EOFException if end of stream occurs before eight bytes
* have been read.
* @throws IOException if an I/O error occurs.
*/
public final double readDouble() throws IOException {
return Double.longBitsToDouble(readLong());
}
/**
* @return the next four bytes of this input stream, interpreted as a
* little endian int.
* @throws EOFException if end of stream occurs before four bytes
* have been read.
* @throws IOException if an I/O error occurs.
*/
public final float readFloat() throws IOException {
return Float.intBitsToFloat(readInt());
}
/**
* Sets the file-pointer offset, measured from the beginning of this
* file, at which the next read or write occurs. The offset may be
* set beyond the end of the file. Setting the offset beyond the end
* of the file does not change the file length. The file length will
* change only by writing after the offset has been set beyond the end
* of the file.
*
* @param pos the offset position, measured in bytes from the
* beginning of the file, at which to set the file
* pointer.
* @exception IOException if pos is less than
* 0 or if an I/O error occurs.
*/
public void seek(final long pos) throws IOException {
mFile.seek(pos);
}
public void setLength(final long newLength) throws IOException {
mFile.setLength(newLength);
}
public int skipBytes(final int n) throws IOException {
return mFile.skipBytes(n);
}
public void write(final byte[] b) throws IOException {
mFile.write(b);
}
public void write(final byte[] b, final int off, final int len) throws IOException {
mFile.write(b, off, len);
}
public void write(final int b) throws IOException {
mFile.write(b);
}
/**
* Writes a boolean to the underlying output stream as
* a single byte. If the argument is true, the byte value 1 is written.
* If the argument is false, the byte value 0 in written.
*
* @param pBoolean the boolean value to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void writeBoolean(boolean pBoolean) throws IOException {
if (pBoolean) {
write(1);
}
else {
write(0);
}
}
/**
* Writes out a byte to the underlying output stream
*
* @param pByte the byte value to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void writeByte(int pByte) throws IOException {
mFile.write(pByte);
}
/**
* Writes a two byte short to the underlying output stream in
* little endian order, low byte first.
*
* @param pShort the short to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void writeShort(int pShort) throws IOException {
mFile.write(pShort & 0xFF);
mFile.write((pShort >>> 8) & 0xFF);
}
/**
* Writes a two byte char to the underlying output stream
* in little endian order, low byte first.
*
* @param pChar the char value to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void writeChar(int pChar) throws IOException {
mFile.write(pChar & 0xFF);
mFile.write((pChar >>> 8) & 0xFF);
}
/**
* Writes a four-byte int to the underlying output stream
* in little endian order, low byte first, high byte last
*
* @param pInt the int to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void writeInt(int pInt) throws IOException {
mFile.write(pInt & 0xFF);
mFile.write((pInt >>> 8) & 0xFF);
mFile.write((pInt >>> 16) & 0xFF);
mFile.write((pInt >>> 24) & 0xFF);
}
/**
* Writes an eight-byte long to the underlying output stream
* in little endian order, low byte first, high byte last
*
* @param pLong the long to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void writeLong(long pLong) throws IOException {
mFile.write((int) pLong & 0xFF);
mFile.write((int) (pLong >>> 8) & 0xFF);
mFile.write((int) (pLong >>> 16) & 0xFF);
mFile.write((int) (pLong >>> 24) & 0xFF);
mFile.write((int) (pLong >>> 32) & 0xFF);
mFile.write((int) (pLong >>> 40) & 0xFF);
mFile.write((int) (pLong >>> 48) & 0xFF);
mFile.write((int) (pLong >>> 56) & 0xFF);
}
/**
* Writes a 4 byte Java float to the underlying output stream in
* little endian order.
*
* @param f the float value to be written.
* @throws IOException if an I/O error occurs.
*/
public final void writeFloat(float f) throws IOException {
writeInt(Float.floatToIntBits(f));
}
/**
* Writes an 8 byte Java double to the underlying output stream in
* little endian order.
*
* @param d the double value to be written.
* @throws IOException if an I/O error occurs.
*/
public final void writeDouble(double d) throws IOException {
writeLong(Double.doubleToLongBits(d));
}
/**
* Writes a string to the underlying output stream as a sequence of
* bytes. Each character is written to the data output stream as
* if by the writeByte() method.
*
* @param pString the String value to be written.
* @throws IOException if the underlying stream throws an IOException.
* @see #writeByte(int)
* @see #mFile
*/
public void writeBytes(String pString) throws IOException {
int length = pString.length();
for (int i = 0; i < length; i++) {
mFile.write((byte) pString.charAt(i));
}
}
/**
* Writes a string to the underlying output stream as a sequence of
* characters. Each character is written to the data output stream as
* if by the writeChar method.
*
* @param pString a String value to be written.
* @throws IOException if the underlying stream throws an IOException.
* @see #writeChar(int)
* @see #mFile
*/
public void writeChars(String pString) throws IOException {
int length = pString.length();
for (int i = 0; i < length; i++) {
int c = pString.charAt(i);
mFile.write(c & 0xFF);
mFile.write((c >>> 8) & 0xFF);
}
}
/**
* Writes a string of no more than 65,535 characters
* to the underlying output stream using UTF-8
* encoding. This method first writes a two byte short
* in big endian order as required by the
* UTF-8 specification. This gives the number of bytes in the
* UTF-8 encoded version of the string, not the number of characters
* in the string. Next each character of the string is written
* using the UTF-8 encoding for the character.
*
* @param pString the string to be written.
* @throws UTFDataFormatException if the string is longer than
* 65,535 characters.
* @throws IOException if the underlying stream throws an IOException.
*/
public void writeUTF(String pString) throws IOException {
int numchars = pString.length();
int numbytes = 0;
for (int i = 0; i < numchars; i++) {
int c = pString.charAt(i);
if ((c >= 0x0001) && (c <= 0x007F)) {
numbytes++;
}
else if (c > 0x07FF) {
numbytes += 3;
}
else {
numbytes += 2;
}
}
if (numbytes > 65535) {
throw new UTFDataFormatException();
}
mFile.write((numbytes >>> 8) & 0xFF);
mFile.write(numbytes & 0xFF);
for (int i = 0; i < numchars; i++) {
int c = pString.charAt(i);
if ((c >= 0x0001) && (c <= 0x007F)) {
mFile.write(c);
}
else if (c > 0x07FF) {
mFile.write(0xE0 | ((c >> 12) & 0x0F));
mFile.write(0x80 | ((c >> 6) & 0x3F));
mFile.write(0x80 | (c & 0x3F));
}
else {
mFile.write(0xC0 | ((c >> 6) & 0x1F));
mFile.write(0x80 | (c & 0x3F));
}
}
}
}
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