package org.apache.lucene.store;
/**
* 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.
*/
import org.apache.lucene.util.BytesRef;
/** @lucene.experimental */
public final class ByteArrayDataInput extends DataInput {
private byte[] bytes;
private int pos;
private int limit;
public ByteArrayDataInput(byte[] bytes) {
reset(bytes);
}
public ByteArrayDataInput(byte[] bytes, int offset, int len) {
reset(bytes, offset, len);
}
public ByteArrayDataInput() {
reset(BytesRef.EMPTY_BYTES);
}
public void reset(byte[] bytes) {
reset(bytes, 0, bytes.length);
}
public int getPosition() {
return pos;
}
public void reset(byte[] bytes, int offset, int len) {
this.bytes = bytes;
pos = offset;
limit = offset + len;
}
public boolean eof() {
return pos == limit;
}
public void skipBytes(int count) {
pos += count;
assert pos <= limit;
}
@Override
public short readShort() {
return (short) (((bytes[pos++] & 0xFF) << 8) | (bytes[pos++] & 0xFF));
}
@Override
public int readInt() {
assert pos+4 <= limit;
return ((bytes[pos++] & 0xFF) << 24) | ((bytes[pos++] & 0xFF) << 16)
| ((bytes[pos++] & 0xFF) << 8) | (bytes[pos++] & 0xFF);
}
@Override
public long readLong() {
assert pos+8 <= limit;
final int i1 = ((bytes[pos++] & 0xff) << 24) | ((bytes[pos++] & 0xff) << 16) |
((bytes[pos++] & 0xff) << 8) | (bytes[pos++] & 0xff);
final int i2 = ((bytes[pos++] & 0xff) << 24) | ((bytes[pos++] & 0xff) << 16) |
((bytes[pos++] & 0xff) << 8) | (bytes[pos++] & 0xff);
return (((long)i1) << 32) | (i2 & 0xFFFFFFFFL);
}
@Override
public int readVInt() {
checkBounds();
byte b = bytes[pos++];
int i = b & 0x7F;
for (int shift = 7; (b & 0x80) != 0; shift += 7) {
checkBounds();
b = bytes[pos++];
i |= (b & 0x7F) << shift;
}
return i;
}
@Override
public long readVLong() {
checkBounds();
byte b = bytes[pos++];
long i = b & 0x7F;
for (int shift = 7; (b & 0x80) != 0; shift += 7) {
checkBounds();
b = bytes[pos++];
i |= (b & 0x7FL) << shift;
}
return i;
}
// NOTE: AIOOBE not EOF if you read too much
@Override
public byte readByte() {
checkBounds();
return bytes[pos++];
}
// NOTE: AIOOBE not EOF if you read too much
@Override
public void readBytes(byte[] b, int offset, int len) {
assert pos + len <= limit;
System.arraycopy(bytes, pos, b, offset, len);
pos += len;
}
private boolean checkBounds() {
assert pos < limit;
return true;
}
}