package org.mp4parser.streaming.input.mp4;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import static org.mp4parser.tools.CastUtils.l2i;
public class DiscardingByteArrayOutputStream extends OutputStream {
/**
* The buffer where data is stored.
*/
protected byte buf[];
/**
* The number of valid bytes in the buffer.
*/
protected int count;
protected long startOffset = 0;
/**
* Creates a new byte array output stream. The buffer capacity is
* initially 32 bytes, though its size increases if necessary.
*/
public DiscardingByteArrayOutputStream() {
this(32);
}
/**
* Creates a new byte array output stream, with a buffer capacity of
* the specified size, in bytes.
*
* @param size the initial size.
* @throws IllegalArgumentException if size is negative.
*/
public DiscardingByteArrayOutputStream(int size) {
if (size < 0) {
throw new IllegalArgumentException("Negative initial size: "
+ size);
}
buf = new byte[size];
}
public byte[] get(long start, int count) {
byte[] result = new byte[count];
try {
System.arraycopy(buf, l2i(start - startOffset), result, 0, count);
} catch (ArrayIndexOutOfBoundsException e) {
System.out.println("start: " + start + " count: " + count + " startOffset:" + startOffset + " count:" + count + " len(buf):" + buf.length + " (start - startOffset):" + (start - startOffset));
throw e;
}
return result;
}
/**
* 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);
}
/**
* 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 < 0) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
newCapacity = Integer.MAX_VALUE;
}
buf = Arrays.copyOf(buf, newCapacity);
}
/**
* Writes the specified byte to this byte array output stream.
*
* @param b the byte to be written.
*/
public synchronized void write(int b) {
ensureCapacity(count + 1);
buf[count] = (byte) b;
count += 1;
}
/**
* Writes <code>len</code> bytes from the specified byte array
* starting at offset <code>off</code> 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.
*/
public synchronized 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;
}
/**
* Resets the <code>count</code> 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#count
*/
public synchronized 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 synchronized byte toByteArray()[] {
return Arrays.copyOf(buf, count);
}
/**
* Returns the current size of the buffer.
*
* @return the value of the <code>count</code> field, which is the number
* of valid bytes in this output stream.
* @see java.io.ByteArrayOutputStream#count
*/
public synchronized 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 <tt>String</tt>
* 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
*/
public synchronized String toString() {
return new String(buf, 0, count);
}
/**
* Closing a <tt>ByteArrayOutputStream</tt> has no effect. The methods in
* this class can be called after the stream has been closed without
* generating an <tt>IOException</tt>.
*/
public void close() throws IOException {
}
/**
* Returns the last index that is available.
*
* @return the overall size (not taking discarded bytes into account)
*/
public synchronized long available() {
return startOffset + count;
}
public synchronized void discardTo(long n) {
//System.err.println("discard up to pos " + n);
System.arraycopy(buf, l2i(n - startOffset), buf, 0, l2i(buf.length - (n - startOffset)));
count -= (n - startOffset);
startOffset = n;
}
}