net.openhft.chronicle.bytes.StreamingInputStream Maven / Gradle / Ivy
/*
* Copyright (c) 2016-2022 chronicle.software
*
* https://chronicle.software
*
* Licensed 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 net.openhft.chronicle.bytes;
import net.openhft.chronicle.bytes.internal.NoBytesStore;
import net.openhft.chronicle.core.annotation.NonNegative;
import org.jetbrains.annotations.NotNull;
import java.io.IOException;
import java.io.InputStream;
import java.nio.BufferUnderflowException;
/**
* A special kind of InputStream implementation which reads data from a StreamingDataInput instance.
*
* This class provides a way to connect APIs expecting an InputStream with data sources
* encapsulated in StreamingDataInput instances.
*
* @see StreamingDataInput
* @see InputStream
*/
@SuppressWarnings("rawtypes")
public class StreamingInputStream extends InputStream {
private StreamingDataInput in;
/**
* Constructs a new StreamingInputStream instance and initializes the data source as an empty ByteStore.
*/
public StreamingInputStream() {
this(NoBytesStore.NO_BYTES);
}
/**
* Constructs a new StreamingInputStream instance with a specific StreamingDataInput as the data source.
*
* @param in the StreamingDataInput instance to read data from.
*/
public StreamingInputStream(StreamingDataInput in) {
this.in = in;
}
/**
* Initializes this StreamingInputStream instance with a specific StreamingDataInput as the data source.
*
* @param in the StreamingDataInput instance to read data from.
* @return this StreamingInputStream instance, for chaining.
*/
@NotNull
public StreamingInputStream init(StreamingDataInput in) {
this.in = in;
return this;
}
@Override
public long skip(long n)
throws IOException {
try {
long len = Math.min(in.readRemaining(), n);
in.readSkip(len);
return len;
} catch (BufferUnderflowException | IllegalStateException e) {
throw new IOException(e);
}
}
@Override
public int available()
throws IOException {
return (int) Math.min(Integer.MAX_VALUE, in.readRemaining());
}
@Override
public int read(byte[] b, @NonNegative int off, @NonNegative int len)
throws IOException {
try {
if (len == 0) {
return 0;
}
int len2 = in.read(b, off, len);
return len2 == 0 ? -1 : len2;
} catch (BufferUnderflowException | IllegalStateException e) {
throw new IOException(e);
}
}
@Override
public int read()
throws IOException {
try {
return in.readRemaining() > 0 ? in.readUnsignedByte() : -1;
} catch (IllegalStateException e) {
throw new IOException(e);
}
}
}