/*
* 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 of the copyright holder 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 HOLDER 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.
* <p/>
* <em>Warning:
* <!-- Beware of little indians! -->
* 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.
* </em>
*
* @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 <a href="mailto:harald.kuhr@gmail.no">Harald Kuhr</a>
* @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 file;
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 {
file = new
RandomAccessFile(
pFile,
pMode);
}
public void
close() throws
IOException {
file.
close();
}
public
FileChannel getChannel() {
return
file.
getChannel();
}
public
FileDescriptor getFD() throws
IOException {
return
file.
getFD();
}
public long
getFilePointer() throws
IOException {
return
file.
getFilePointer();
}
public long
length() throws
IOException {
return
file.
length();
}
public int
read() throws
IOException {
return
file.
read();
}
public int
read(final byte[]
b) throws
IOException {
return
file.
read(
b);
}
public int
read(final byte[]
b, final int
off, final int
len) throws
IOException {
return
file.
read(
b,
off,
len);
}
public void
readFully(final byte[]
b) throws
IOException {
file.
readFully(
b);
}
public void
readFully(final byte[]
b, final int
off, final int
len) throws
IOException {
file.
readFully(
b,
off,
len);
}
public
String readLine() throws
IOException {
return
file.
readLine();
}
/**
* Reads a {@code 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 {@code 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 =
file.
read();
if (
b < 0) {
throw new
EOFException();
}
return
b != 0;
}
/**
* Reads a signed {@code byte} from the underlying input stream
* with value between -128 and 127
*
* @return the {@code 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 =
file.
read();
if (
b < 0) {
throw new
EOFException();
}
return (byte)
b;
}
/**
* Reads an unsigned {@code byte} from the underlying
* input stream with value between 0 and 255
*
* @return the {@code 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 =
file.
read();
if (
b < 0) {
throw new
EOFException();
}
return
b;
}
/**
* Reads a two byte signed {@code short} from the underlying
* input stream in little endian order, low byte first.
*
* @return the {@code 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 =
file.
read();
int
byte2 =
file.
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 {@code 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 =
file.
read();
int
byte2 =
file.
read();
if (
byte2 < 0) {
throw new
EOFException();
}
//return ((byte2 << 24) >> 16) + ((byte1 << 24) >> 24);
return (
byte2 << 8) +
byte1;
}
/**
* Reads a two byte Unicode {@code 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 =
file.
read();
int
byte2 =
file.
read();
if (
byte2 < 0) {
throw new
EOFException();
}
return (char) (((
byte2 << 24) >>> 16) + ((
byte1 << 24) >>> 24));
}
/**
* Reads a four byte signed {@code int} from the underlying
* input stream in little endian order, low byte first.
*
* @return the {@code 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 =
file.
read();
int
byte2 =
file.
read();
int
byte3 =
file.
read();
int
byte4 =
file.
read();
if (
byte4 < 0) {
throw new
EOFException();
}
return (
byte4 << 24) + ((
byte3 << 24) >>> 8) + ((
byte2 << 24) >>> 16) + ((
byte1 << 24) >>> 24);
}
/**
* Reads an eight byte signed {@code int} from the underlying
* input stream in little endian order, low byte first.
*
* @return the {@code 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 =
file.
read();
long
byte2 =
file.
read();
long
byte3 =
file.
read();
long
byte4 =
file.
read();
long
byte5 =
file.
read();
long
byte6 =
file.
read();
long
byte7 =
file.
read();
long
byte8 =
file.
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 <b>big</b> 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 =
file.
read();
int
byte2 =
file.
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 {@code 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 {@code 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 {@code pos} is less than
* {@code 0} or if an I/O error occurs.
*/
public void
seek(final long
pos) throws
IOException {
file.
seek(
pos);
}
public void
setLength(final long
newLength) throws
IOException {
file.
setLength(
newLength);
}
public int
skipBytes(final int
n) throws
IOException {
return
file.
skipBytes(
n);
}
public void
write(final byte[]
b) throws
IOException {
file.
write(
b);
}
public void
write(final byte[]
b, final int
off, final int
len) throws
IOException {
file.
write(
b,
off,
len);
}
public void
write(final int
b) throws
IOException {
file.
write(
b);
}
/**
* Writes a {@code 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 {@code 0} in written.
*
* @param pBoolean the {@code 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 {@code byte} to the underlying output stream
*
* @param pByte the {@code byte} value to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void
writeByte(int
pByte) throws
IOException {
file.
write(
pByte);
}
/**
* Writes a two byte {@code short} to the underlying output stream in
* little endian order, low byte first.
*
* @param pShort the {@code short} to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void
writeShort(int
pShort) throws
IOException {
file.
write(
pShort & 0xFF);
file.
write((
pShort >>> 8) & 0xFF);
}
/**
* Writes a two byte {@code char} to the underlying output stream
* in little endian order, low byte first.
*
* @param pChar the {@code char} value to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void
writeChar(int
pChar) throws
IOException {
file.
write(
pChar & 0xFF);
file.
write((
pChar >>> 8) & 0xFF);
}
/**
* Writes a four-byte {@code int} to the underlying output stream
* in little endian order, low byte first, high byte last
*
* @param pInt the {@code int} to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void
writeInt(int
pInt) throws
IOException {
file.
write(
pInt & 0xFF);
file.
write((
pInt >>> 8) & 0xFF);
file.
write((
pInt >>> 16) & 0xFF);
file.
write((
pInt >>> 24) & 0xFF);
}
/**
* Writes an eight-byte {@code long} to the underlying output stream
* in little endian order, low byte first, high byte last
*
* @param pLong the {@code long} to be written.
* @throws IOException if the underlying stream throws an IOException.
*/
public void
writeLong(long
pLong) throws
IOException {
file.
write((int)
pLong & 0xFF);
file.
write((int) (
pLong >>> 8) & 0xFF);
file.
write((int) (
pLong >>> 16) & 0xFF);
file.
write((int) (
pLong >>> 24) & 0xFF);
file.
write((int) (
pLong >>> 32) & 0xFF);
file.
write((int) (
pLong >>> 40) & 0xFF);
file.
write((int) (
pLong >>> 48) & 0xFF);
file.
write((int) (
pLong >>> 56) & 0xFF);
}
/**
* Writes a 4 byte Java float to the underlying output stream in
* little endian order.
*
* @param f the {@code 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 {@code 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 {@code writeByte()} method.
*
* @param pString the {@code String} value to be written.
* @throws IOException if the underlying stream throws an IOException.
* @see #writeByte(int)
* @see #file
*/
public void
writeBytes(
String pString) throws
IOException {
int
length =
pString.
length();
for (int
i = 0;
i <
length;
i++) {
file.
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 {@code writeChar} method.
*
* @param pString a {@code String} value to be written.
* @throws IOException if the underlying stream throws an IOException.
* @see #writeChar(int)
* @see #file
*/
public void
writeChars(
String pString) throws
IOException {
int
length =
pString.
length();
for (int
i = 0;
i <
length;
i++) {
int
c =
pString.
charAt(
i);
file.
write(
c & 0xFF);
file.
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 <b>big</b> 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();
}
file.
write((
numbytes >>> 8) & 0xFF);
file.
write(
numbytes & 0xFF);
for (int
i = 0;
i <
numchars;
i++) {
int
c =
pString.
charAt(
i);
if ((
c >= 0x0001) && (
c <= 0x007F)) {
file.
write(
c);
}
else if (
c > 0x07FF) {
file.
write(0xE0 | ((
c >> 12) & 0x0F));
file.
write(0x80 | ((
c >> 6) & 0x3F));
file.
write(0x80 | (
c & 0x3F));
}
else {
file.
write(0xC0 | ((
c >> 6) & 0x1F));
file.
write(0x80 | (
c & 0x3F));
}
}
}
}