com.itextpdf.text.pdf.MemoryLimitsAwareOutputStream Maven / Gradle / Ivy
package com.itextpdf.text.pdf;
import com.itextpdf.text.pdf.MemoryLimitsAwareException;
import java.io.ByteArrayOutputStream;
import java.util.Arrays;
/**
* This class implements an output stream which can be used for memory limits aware decompression of pdf streams.
*/
class MemoryLimitsAwareOutputStream extends ByteArrayOutputStream {
/**
* The maximum size of array to allocate.
* Attempts to allocate larger arrays will result in an exception.
*/
private static final int DEFAULT_MAX_STREAM_SIZE = Integer.MAX_VALUE - 8;
/**
* The maximum size of array to allocate.
* Attempts to allocate larger arrays will result in an exception.
*/
private int maxStreamSize = DEFAULT_MAX_STREAM_SIZE;
/**
* Creates a new byte array output stream. The buffer capacity is
* initially 32 bytes, though its size increases if necessary.
*/
public MemoryLimitsAwareOutputStream() {
super();
}
/**
* 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 MemoryLimitsAwareOutputStream(int size) {
super(size);
}
/**
* Gets the maximum size which can be occupied by this output stream.
*
* @return the maximum size which can be occupied by this output stream.
*/
public long getMaxStreamSize() {
return maxStreamSize;
}
/**
* Sets the maximum size which can be occupied by this output stream.
*
* @param maxStreamSize the maximum size which can be occupied by this output stream.
* @return this {@link MemoryLimitsAwareOutputStream}
*/
public MemoryLimitsAwareOutputStream setMaxStreamSize(int maxStreamSize) {
this.maxStreamSize = maxStreamSize;
return this;
}
/**
* {@inheritDoc}
*/
@Override
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();
}
int minCapacity = count + len;
if (minCapacity < 0) { // overflow
throw new MemoryLimitsAwareException(MemoryLimitsAwareException.DuringDecompressionSingleStreamOccupiedMoreThanMaxIntegerValue);
}
if (minCapacity > maxStreamSize) {
throw new MemoryLimitsAwareException(MemoryLimitsAwareException.DuringDecompressionSingleStreamOccupiedMoreMemoryThanAllowed);
}
// calculate new capacity
int oldCapacity = buf.length;
int newCapacity = oldCapacity << 1;
if (newCapacity - minCapacity < 0) {
newCapacity = minCapacity;
}
if (newCapacity < 0) { // overflow
throw new MemoryLimitsAwareException(MemoryLimitsAwareException.DuringDecompressionSingleStreamOccupiedMoreThanMaxIntegerValue);
}
if (newCapacity - maxStreamSize > 0) {
newCapacity = maxStreamSize;
byte[] copy = new byte[newCapacity];
System.arraycopy(buf, 0, copy, 0,
Math.min(buf.length, newCapacity));
buf = copy;
}
super.write(b, off, len);
}
}