com.github.davidmoten.util.ByteArrayOutputStreamNoCopyUnsynchronized Maven / Gradle / Ivy
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* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package com.github.davidmoten.util;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;
/**
* This class implements an output stream in which the data is written into a
* byte array. The buffer automatically grows as data is written to it. The data
* can be retrieved using toByteArray() and toString()
* .
*
* Closing a ByteArrayOutputStream has no effect. The methods in this
* class can be called after the stream has been closed without generating an
* IOException.
*
* @author Arthur van Hoff
* @since JDK1.0
*/
public class ByteArrayOutputStreamNoCopyUnsynchronized extends OutputStream {
/**
* The buffer where data is stored.
*/
protected byte buf[];
/**
* The number of valid bytes in the buffer.
*/
protected int count;
/**
* Creates a new byte array output stream. The buffer capacity is initially
* 32 bytes, though its size increases if necessary.
*/
public ByteArrayOutputStreamNoCopyUnsynchronized() {
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 ByteArrayOutputStreamNoCopyUnsynchronized(int size) {
if (size < 0) {
throw new IllegalArgumentException("Negative initial size: " + size);
}
buf = new byte[size];
}
/**
* Increases the capacity if necessary to ensure that it can hold at least
* the number of elements specified by the minimum capacity argument.
*
* @param minCapacity
* the desired minimum capacity
* @throws OutOfMemoryError
* if {@code minCapacity < 0}. This is interpreted as a request
* for the unsatisfiably large capacity
* {@code (long) Integer.MAX_VALUE + (minCapacity - Integer.MAX_VALUE)}
* .
*/
private void ensureCapacity(int minCapacity) {
// overflow-conscious code
if (minCapacity - buf.length > 0)
grow(minCapacity);
}
/**
* 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;
/**
* 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);
buf = Arrays.copyOf(buf, newCapacity);
}
private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
return (minCapacity > MAX_ARRAY_SIZE) ? Integer.MAX_VALUE : MAX_ARRAY_SIZE;
}
/**
* Writes the specified byte to this byte array output stream.
*
* @param b
* the byte to be written.
*/
@Override
public void write(int b) {
ensureCapacity(count + 1);
buf[count] = (byte) b;
count += 1;
}
/**
* Writes len bytes from the specified byte array starting at
* offset off to this byte array output stream.
*
* @param b
* the data.
* @param off
* the start offset in the data.
* @param len
* the number of bytes to write.
*/
@Override
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.
*
* @see java.io.ByteArrayInputStream#reset()
*/
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.
* @see java.io.ByteArrayOutputStream#size()
*/
public byte toByteArray()[] {
return Arrays.copyOf(buf, count);
}
public byte[] toByteArrayNoCopy() {
return buf;
}
/**
* 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.
* @see java.io.ByteArrayOutputStream#size()
*/
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.
* @since JDK1.1
*/
@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
* @since JDK1.1
*/
public String toString(String charsetName) throws UnsupportedEncodingException {
return new String(buf, 0, count, charsetName);
}
/**
* Creates a newly allocated string. Its size is the current size of the
* output stream and the valid contents of the buffer have been copied into
* it. Each character c in the resulting string is constructed from
* the corresponding element b in the byte array such that:
*
*
*
* c == (char) (((hibyte & 0xff) << 8) | (b & 0xff))
*
*
*
*
* @deprecated This method does not properly convert bytes into characters.
* As of JDK 1.1, the preferred way to do this is via the
* toString(String enc) method, which takes an
* encoding-name argument, or the toString()
* method, which uses the platform's default character encoding.
*
* @param hibyte
* the high byte of each resulting Unicode character.
* @return the current contents of the output stream, as a string.
* @see java.io.ByteArrayOutputStream#size()
* @see java.io.ByteArrayOutputStream#toString(String)
* @see java.io.ByteArrayOutputStream#toString()
*/
@Deprecated
public String toString(int hibyte) {
return new String(buf, hibyte, 0, count);
}
/**
* Closing a ByteArrayOutputStream has no effect. The methods in
* this class can be called after the stream has been closed without
* generating an IOException.
*/
@Override
public void close() throws IOException {
}
}