org.apache.drill.exec.store.ResourceInputStream.java Source code

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Here is the source code for org.apache.drill.exec.store.ResourceInputStream.java

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/*
 * 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.apache.drill.exec.store;

import java.io.ByteArrayInputStream;
import java.io.EOFException;
import java.io.IOException;

import org.apache.hadoop.fs.PositionedReadable;
import org.apache.hadoop.fs.Seekable;

import com.google.common.base.Preconditions;

public class ResourceInputStream extends ByteArrayInputStream implements Seekable, PositionedReadable {
    static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(ResourceInputStream.class);

    public ResourceInputStream(byte[] bytes) {
        super(bytes);
    }

    @Override
    public void readFully(long position, byte[] buffer) throws IOException {
        int l = read(position, buffer, 0, buffer.length);
        if (l < buffer.length) {
            throw new EOFException();
        }
    }

    public int read(long position, byte b[], int off, int len) {
        Preconditions.checkNotNull(b);
        Preconditions.checkPositionIndexes(off, off + len, b.length);

        int start = (int) position;

        if (start >= count) {
            return -1;
        }

        int avail = count - start;
        if (len > avail) {
            len = avail;
        }
        if (len <= 0) {
            return 0;
        }
        System.arraycopy(buf, start, b, off, len);
        return len;
    }

    @Override
    public void readFully(long position, byte[] buffer, int offset, int length) throws IOException {
        int l = read(position, buffer, offset, length);
        if (l < length) {
            throw new EOFException();
        }
    }

    @Override
    public long getPos() throws IOException {
        return pos;
    }

    @Override
    public int read(byte[] b) throws IOException {
        int l = read(pos, b, 0, b.length);
        pos += l;
        return l;
    }

    @Override
    public boolean seekToNewSource(long arg0) throws IOException {
        seek(arg0);
        return true;
    }

    @Override
    public void seek(long arg0) throws IOException {
        if (buf.length > arg0) {
            pos = (int) arg0;
        } else {
            throw new EOFException();
        }
    }
}