org.apache.commons.javaflow.spi.FastByteArrayOutputStream Maven / Gradle / Ivy
/**
* Copyright 2013-2022 Valery Silaev (http://vsilaev.com)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.javaflow.spi;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
public class FastByteArrayOutputStream extends OutputStream {
/**
* The buffer where data is stored.
*/
private byte buf[];
/**
* The number of valid bytes in the buffer.
*/
private int count;
/**
* Creates a new byte array output stream. The buffer capacity is
* initially 32 bytes, though its size increases if necessary.
*/
public FastByteArrayOutputStream() {
this(32);
}
/**
* Creates a new byte array output stream, with a buffer capacity of
* the specified size, in bytes.
*
* @param size the initial size.
* @exception IllegalArgumentException if size is negative.
*/
public FastByteArrayOutputStream(int size) {
if (size < 0) {
throw new IllegalArgumentException("Negative initial size: " + size);
}
buf = new byte[size];
}
public void write(int b) {
ensureCapacity(count + 1);
buf[count] = (byte) b;
count += 1;
}
public void write(byte b[], int off, int len) {
if ((off < 0) ||
(off > b.length) ||
(len < 0) ||
((off + len) - b.length > 0)) {
throw new IndexOutOfBoundsException();
}
ensureCapacity(count + len);
System.arraycopy(b, off, buf, count, len);
count += len;
}
/**
* Writes the complete contents of this byte array output stream to
* the specified output stream argument, as if by calling the output
* stream's write method using out.write(buf, 0, count).
*
* @param out the output stream to which to write the data.
* @exception IOException if an I/O error occurs.
*/
public void writeTo(OutputStream out) throws IOException {
out.write(buf, 0, count);
}
/**
* Resets the count field of this byte array output
* stream to zero, so that all currently accumulated output in the
* output stream is discarded. The output stream can be used again,
* reusing the already allocated buffer space.
*/
public void reset() {
count = 0;
}
/**
* Creates a newly allocated byte array. Its size is the current
* size of this output stream and the valid contents of the buffer
* have been copied into it.
*
* @return the current contents of this output stream, as a byte array.
*/
public byte[] toByteArray() {
byte[] result = new byte[count];
System.arraycopy(buf, 0, result, 0, count);
return result;
}
public byte[] unsafeBytes() {
if (count == buf.length) {
return buf;
} else {
return toByteArray();
}
}
/**
* Returns the current size of the buffer.
*
* @return the value of the count field, which is the number
* of valid bytes in this output stream.
*/
public int size() {
return count;
}
/**
* Converts the buffer's contents into a string decoding bytes using the
* platform's default character set. The length of the new String
* is a function of the character set, and hence may not be equal to the
* size of the buffer.
*
* This method always replaces malformed-input and unmappable-character
* sequences with the default replacement string for the platform's
* default character set. The {@linkplain java.nio.charset.CharsetDecoder}
* class should be used when more control over the decoding process is
* required.
*
* @return String decoded from the buffer's contents.
*
*/
@Override
public String toString() {
return new String(buf, 0, count);
}
/**
* Converts the buffer's contents into a string by decoding the bytes using
* the named {@link java.nio.charset.Charset charset}. The length of the new
* String is a function of the charset, and hence may not be equal
* to the length of the byte array.
*
*
This method always replaces malformed-input and unmappable-character
* sequences with this charset's default replacement string. The {@link
* java.nio.charset.CharsetDecoder} class should be used when more control
* over the decoding process is required.
*
* @param charsetName the name of a supported
* {@link java.nio.charset.Charset charset}
* @return String decoded from the buffer's contents.
* @exception UnsupportedEncodingException
* If the named charset is not supported
*/
public String toString(String charsetName) throws UnsupportedEncodingException {
return new String(buf, 0, count, charsetName);
}
@Override
public void close() {
}
private void ensureCapacity(int minCapacity) {
// overflow-conscious code
if (minCapacity - buf.length > 0)
grow(minCapacity);
}
/**
* Increases the capacity to ensure that it can hold at least the
* number of elements specified by the minimum capacity argument.
*
* @param minCapacity the desired minimum capacity
*/
private void grow(int minCapacity) {
// overflow-conscious code
int oldCapacity = buf.length;
int newCapacity = oldCapacity << 1;
if (newCapacity - minCapacity < 0)
newCapacity = minCapacity;
if (newCapacity - MAX_ARRAY_SIZE > 0)
newCapacity = hugeCapacity(minCapacity);
byte[] newBuf = new byte[newCapacity];
System.arraycopy(buf, 0, newBuf, 0, count);
buf = newBuf;
}
private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
return (minCapacity > MAX_ARRAY_SIZE) ?
Integer.MAX_VALUE :
MAX_ARRAY_SIZE;
}
/**
* The maximum size of array to allocate.
* Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in
* OutOfMemoryError: Requested array size exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
}