org.trypticon.luceneupgrader.lucene6.internal.lucene.store.RAMOutputStream Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.trypticon.luceneupgrader.lucene6.internal.lucene.store;
import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.zip.CRC32;
import java.util.zip.Checksum;
import org.trypticon.luceneupgrader.lucene6.internal.lucene.util.Accountable;
import org.trypticon.luceneupgrader.lucene6.internal.lucene.util.Accountables;
/**
* A memory-resident {@link IndexOutput} implementation.
*
* @lucene.internal
*/
public class RAMOutputStream extends IndexOutput implements Accountable {
static final int BUFFER_SIZE = 1024;
private final RAMFile file;
private byte[] currentBuffer;
private int currentBufferIndex;
private int bufferPosition;
private long bufferStart;
private int bufferLength;
private final Checksum crc;
/** Construct an empty output buffer. */
public RAMOutputStream() {
this("noname", new RAMFile(), false);
}
/** Creates this, with no name. */
public RAMOutputStream(RAMFile f, boolean checksum) {
this("noname", f, checksum);
}
/** Creates this, with specified name. */
public RAMOutputStream(String name, RAMFile f, boolean checksum) {
super("RAMOutputStream(name=\"" + name + "\")", name);
file = f;
// make sure that we switch to the
// first needed buffer lazily
currentBufferIndex = -1;
currentBuffer = null;
if (checksum) {
crc = new BufferedChecksum(new CRC32());
} else {
crc = null;
}
}
/** Copy the current contents of this buffer to the provided {@link DataOutput}. */
public void writeTo(DataOutput out) throws IOException {
flush();
final long end = file.length;
long pos = 0;
int buffer = 0;
while (pos < end) {
int length = BUFFER_SIZE;
long nextPos = pos + length;
if (nextPos > end) { // at the last buffer
length = (int)(end - pos);
}
out.writeBytes(file.getBuffer(buffer++), length);
pos = nextPos;
}
}
/** Copy the current contents of this buffer to output
* byte array */
public void writeTo(byte[] bytes, int offset) throws IOException {
flush();
final long end = file.length;
long pos = 0;
int buffer = 0;
int bytesUpto = offset;
while (pos < end) {
int length = BUFFER_SIZE;
long nextPos = pos + length;
if (nextPos > end) { // at the last buffer
length = (int)(end - pos);
}
System.arraycopy(file.getBuffer(buffer++), 0, bytes, bytesUpto, length);
bytesUpto += length;
pos = nextPos;
}
}
/** Resets this to an empty file. */
public void reset() {
currentBuffer = null;
currentBufferIndex = -1;
bufferPosition = 0;
bufferStart = 0;
bufferLength = 0;
file.setLength(0);
if (crc != null) {
crc.reset();
}
}
@Override
public void close() throws IOException {
flush();
}
@Override
public void writeByte(byte b) throws IOException {
if (bufferPosition == bufferLength) {
currentBufferIndex++;
switchCurrentBuffer();
}
if (crc != null) {
crc.update(b);
}
currentBuffer[bufferPosition++] = b;
}
@Override
public void writeBytes(byte[] b, int offset, int len) throws IOException {
assert b != null;
if (crc != null) {
crc.update(b, offset, len);
}
while (len > 0) {
if (bufferPosition == bufferLength) {
currentBufferIndex++;
switchCurrentBuffer();
}
int remainInBuffer = currentBuffer.length - bufferPosition;
int bytesToCopy = len < remainInBuffer ? len : remainInBuffer;
System.arraycopy(b, offset, currentBuffer, bufferPosition, bytesToCopy);
offset += bytesToCopy;
len -= bytesToCopy;
bufferPosition += bytesToCopy;
}
}
private final void switchCurrentBuffer() {
if (currentBufferIndex == file.numBuffers()) {
currentBuffer = file.addBuffer(BUFFER_SIZE);
} else {
currentBuffer = file.getBuffer(currentBufferIndex);
}
bufferPosition = 0;
bufferStart = (long) BUFFER_SIZE * (long) currentBufferIndex;
bufferLength = currentBuffer.length;
}
private void setFileLength() {
long pointer = bufferStart + bufferPosition;
if (pointer > file.length) {
file.setLength(pointer);
}
}
/** Forces any buffered output to be written. */
protected void flush() throws IOException {
setFileLength();
}
@Override
public long getFilePointer() {
return currentBufferIndex < 0 ? 0 : bufferStart + bufferPosition;
}
/** Returns byte usage of all buffers. */
@Override
public long ramBytesUsed() {
return (long) file.numBuffers() * (long) BUFFER_SIZE;
}
@Override
public Collection getChildResources() {
return Collections.singleton(Accountables.namedAccountable("file", file));
}
@Override
public long getChecksum() throws IOException {
if (crc == null) {
throw new IllegalStateException("internal RAMOutputStream created with checksum disabled");
} else {
return crc.getValue();
}
}
}