com.upokecenter.util.DataIO Maven / Gradle / Ivy
package com.upokecenter.util;
/*
Written by Peter O. in 2014.
Any copyright is dedicated to the Public Domain.
http://creativecommons.org/publicdomain/zero/1.0/
If you like this, you should donate to Peter O.
at: http://upokecenter.dreamhosters.com/articles/donate-now-2/
*/
import java.io.*;
/**
* Convenience class that contains static methods for wrapping byte arrays and
* streams into byte readers and byte writers.
*/
public final class DataIO {
private DataIO() {
}
private static final class ByteArrayTransform implements IByteReader {
private byte[] bytes;
private int offset;
private int endOffset;
public ByteArrayTransform (byte[] bytes, int offset, int length) {
this.bytes = bytes;
this.offset = offset;
this.endOffset = offset + length;
}
/**
* This is an internal method.
* @return A 32-bit signed integer.
*/
public int read() {
if (this.offset >= this.endOffset) {
return -1;
}
int b = this.bytes[this.offset++];
return ((int)b) & 0xff;
}
}
private static final class WrappedStream implements IByteReader {
private InputStream stream;
public WrappedStream (InputStream stream) {
this.stream = stream;
}
/**
* This is an internal method.
* @return A 32-bit signed integer.
*/
public int read() {
try {
return this.stream.read();
} catch (IOException ex) {
throw new IllegalStateException(ex.getMessage(), ex);
}
}
}
private static final class WrappedOutputStreamFromByteWriter implements IWriter {
private IByteWriter output;
public WrappedOutputStreamFromByteWriter (IByteWriter output) {
this.output = output;
}
/**
* This is an internal method.
* @param byteValue A 32-bit signed integer.
*/
public void write(int byteValue) {
this.output.write((byte)byteValue);
}
/**
* This is an internal method.
* @param bytes A byte array.
* @param offset A zero-based index showing where the desired portion of
* "bytes" begins.
* @param length The length, in bytes, of the desired portion of "bytes" (but
* not more than "bytes" 's length).
* @throws NullPointerException The parameter {@code bytes} is null.
* @throws IllegalArgumentException Either {@code offset} or {@code length} is less
* than 0 or greater than {@code bytes} 's length, or {@code bytes} 's
* length minus {@code offset} is less than {@code length}.
*/
public void write(byte[] bytes, int offset, int length) {
if (bytes == null) {
throw new NullPointerException("bytes");
}
if (offset < 0) {
throw new IllegalArgumentException("offset (" + offset +
") is less than " + 0);
}
if (offset > bytes.length) {
throw new IllegalArgumentException("offset (" + offset + ") is more than " +
bytes.length);
}
if (length < 0) {
throw new IllegalArgumentException("length (" + length +
") is less than " + 0);
}
if (length > bytes.length) {
throw new IllegalArgumentException("length (" + length + ") is more than " +
bytes.length);
}
if (bytes.length - offset < length) {
throw new IllegalArgumentException("bytes's length minus " + offset + " (" +
(bytes.length - offset) + ") is less than " + length);
}
for (int i = 0; i < length; ++i) {
this.output.write((byte)bytes[i]);
}
}
}
private static final class WrappedOutputStream implements IWriter {
private OutputStream output;
public WrappedOutputStream (OutputStream output) {
this.output = output;
}
/**
* This is an internal method.
* @param byteValue A 32-bit signed integer.
*/
public void write(int byteValue) {
try {
this.output.write((byte)byteValue);
} catch (IOException ex) {
throw new IllegalStateException(ex.getMessage(), ex);
}
}
/**
* This is an internal method.
* @param bytes A byte array.
* @param offset A zero-based index showing where the desired portion of
* "bytes" begins.
* @param length The length, in bytes, of the desired portion of "bytes" (but
* not more than "bytes" 's length).
* @throws IllegalArgumentException Either {@code offset} or {@code length} is less
* than 0 or greater than {@code bytes} 's length, or {@code bytes} 's
* length minus {@code offset} is less than {@code length}.
* @throws NullPointerException The parameter {@code bytes} is null.
*/
public void write(byte[] bytes, int offset, int length) {
try {
this.output.write(bytes, offset, length);
} catch (IOException ex) {
throw new IllegalStateException(ex.getMessage(), ex);
}
}
}
/**
* Wraps a byte array into a byte reader. The reader will start at the
* beginning of the byte array. In the .NET implementation, this
* method is implemented as an extension method to any object
* implementing byte[] and can be called as follows:
* bytes.ToTransform(). If the object's class already has a
* ToTransform method with the same parameters, that method takes
* precedence over this extension method.
* @param bytes The byte array to wrap.
* @return A byte reader wrapping the byte array.
* @throws NullPointerException The parameter {@code bytes} is null.
*/
public static IByteReader ToTransform(byte[] bytes) {
if (bytes == null) {
throw new NullPointerException("bytes");
}
return new ByteArrayTransform(bytes, 0, bytes.length);
}
/**
* Wraps a portion of a byte array into a byte reader object. In the .NET
* implementation, this method is implemented as an extension method to
* any object implementing byte[] and can be called as follows:
* bytes.ToTransform(offset, length). If the object's class
* already has a ToTransform method with the same parameters, that
* method takes precedence over this extension method.
* @param bytes The byte array to wrap.
* @param offset A zero-based index showing where the desired portion of
* "bytes" begins.
* @param length The length, in bytes, of the desired portion of "bytes" (but
* not more than "bytes" 's length).
* @return A byte reader wrapping the byte array.
* @throws NullPointerException The parameter {@code bytes} is null.
* @throws IllegalArgumentException Either {@code offset} or {@code length} is less
* than 0 or greater than {@code bytes} 's length, or {@code bytes} 's
* length minus {@code offset} is less than {@code length}.
*/
public static IByteReader ToTransform(
byte[] bytes,
int offset,
int length) {
if (bytes == null) {
throw new NullPointerException("bytes");
}
if (offset < 0) {
throw new IllegalArgumentException("offset (" + offset +
") is less than " + 0);
}
if (offset > bytes.length) {
throw new IllegalArgumentException("offset (" + offset + ") is more than " +
bytes.length);
}
if (length < 0) {
throw new IllegalArgumentException("length (" + length +
") is less than " + 0);
}
if (length > bytes.length) {
throw new IllegalArgumentException("length (" + length + ") is more than " +
bytes.length);
}
if (bytes.length - offset < length) {
throw new IllegalArgumentException("bytes's length minus " + offset + " (" +
(bytes.length - offset) + ") is less than " + length);
}
return new ByteArrayTransform(bytes, offset, length);
}
/**
* Wraps an input stream into a reader object. If an IOException is thrown by
* the input stream, the reader object throws IllegalStateException
* instead. In the .NET implementation, this method is implemented as
* an extension method to any object implementing InputStream and can be
* called as follows: input.ToTransform(). If the object's class
* already has a ToTransform method with the same parameters, that
* method takes precedence over this extension method.
* @param input The input stream to wrap.
* @return A byte reader wrapping the input stream.
* @throws NullPointerException The parameter {@code input} is null.
*/
public static IByteReader ToTransform(InputStream input) {
if (input == null) {
throw new NullPointerException("input");
}
return new WrappedStream(input);
}
/**
* Wraps an output stream into a writer object. If an IOException is thrown by
* the input stream, the writer object throws IllegalStateException
* instead. In the .NET implementation, this method is implemented as
* an extension method to any object implementing InputStream and can be
* called as follows: output.ToWriter(). If the object's class
* already has a ToWriter method with the same parameters, that method
* takes precedence over this extension method.
* @param output Output stream to wrap.
* @return A byte writer that wraps the given output stream.
* @throws NullPointerException The parameter {@code output} is null.
*/
public static IWriter ToWriter(OutputStream output) {
if (output == null) {
throw new NullPointerException("output");
}
return new WrappedOutputStream(output);
}
/**
* Wraps a byte writer (one that only implements a ReadByte method) to a writer
* (one that also implements a three-parameter Read method.) In the
* .NET implementation, this method is implemented as an extension
* method to any object implementing IByteWriter and can be called as
* follows: output.ToWriter(). If the object's class already has
* a ToWriter method with the same parameters, that method takes
* precedence over this extension method.
* @param output A byte stream.
* @return A writer that wraps the given stream.
* @throws NullPointerException The parameter {@code output} is null.
*/
public static IWriter ToWriter(IByteWriter output) {
if (output == null) {
throw new NullPointerException("output");
}
return new WrappedOutputStreamFromByteWriter(output);
}
}
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