UnsynchronizedByteArrayInputStream.java
/*
* 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.commons.io.input;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Objects;
import org.apache.commons.io.build.AbstractOrigin;
import org.apache.commons.io.build.AbstractStreamBuilder;
/**
* This is an alternative to {@link java.io.ByteArrayInputStream} which removes the synchronization overhead for non-concurrent access; as such this class is
* not thread-safe.
* <p>
* To build an instance, use {@link Builder}.
* </p>
*
* @see Builder
* @see ByteArrayInputStream
* @since 2.7
*/
//@NotThreadSafe
public class UnsynchronizedByteArrayInputStream extends InputStream {
// @formatter:off
/**
* Builds a new {@link UnsynchronizedByteArrayInputStream}.
*
* <p>
* Using a Byte Array:
* </p>
* <pre>{@code
* UnsynchronizedByteArrayInputStream s = UnsynchronizedByteArrayInputStream.builder()
* .setByteArray(byteArray)
* .setOffset(0)
* .setLength(byteArray.length)
* .get();
* }
* </pre>
* <p>
* Using File IO:
* </p>
* <pre>{@code
* UnsynchronizedByteArrayInputStream s = UnsynchronizedByteArrayInputStream.builder()
* .setFile(file)
* .setOffset(0)
* .setLength(byteArray.length)
* .get();
* }
* </pre>
* <p>
* Using NIO Path:
* </p>
* <pre>{@code
* UnsynchronizedByteArrayInputStream s = UnsynchronizedByteArrayInputStream.builder()
* .setPath(path)
* .setOffset(0)
* .setLength(byteArray.length)
* .get();
* }
* </pre>
*
* @see #get()
*/
// @formatter:on
public static class Builder extends AbstractStreamBuilder<UnsynchronizedByteArrayInputStream, Builder> {
private int offset;
private int length;
/**
* Builds a new {@link UnsynchronizedByteArrayInputStream}.
* <p>
* You must set input that supports {@code byte[]} on this builder, otherwise, this method throws an exception.
* </p>
* <p>
* This builder use the following aspects:
* </p>
* <ul>
* <li>{@code byte[]}</li>
* <li>offset</li>
* <li>length</li>
* </ul>
*
* @return a new instance.
* @throws UnsupportedOperationException if the origin cannot provide a byte[].
* @throws IllegalStateException if the {@code origin} is {@code null}.
* @see AbstractOrigin#getByteArray()
*/
@Override
public UnsynchronizedByteArrayInputStream get() throws IOException {
return new UnsynchronizedByteArrayInputStream(checkOrigin().getByteArray(), offset, length);
}
@Override
public Builder setByteArray(final byte[] origin) {
length = Objects.requireNonNull(origin, "origin").length;
return super.setByteArray(origin);
}
/**
* Sets the length.
*
* @param length Must be greater or equal to 0.
* @return this.
*/
public Builder setLength(final int length) {
if (length < 0) {
throw new IllegalArgumentException("length cannot be negative");
}
this.length = length;
return this;
}
/**
* Sets the offset.
*
* @param offset Must be greater or equal to 0.
* @return this.
*/
public Builder setOffset(final int offset) {
if (offset < 0) {
throw new IllegalArgumentException("offset cannot be negative");
}
this.offset = offset;
return this;
}
}
/**
* The end of stream marker.
*/
public static final int END_OF_STREAM = -1;
/**
* Constructs a new {@link Builder}.
*
* @return a new {@link Builder}.
*/
public static Builder builder() {
return new Builder();
}
private static int minPosLen(final byte[] data, final int defaultValue) {
requireNonNegative(defaultValue, "defaultValue");
return Math.min(defaultValue, data.length > 0 ? data.length : defaultValue);
}
private static int requireNonNegative(final int value, final String name) {
if (value < 0) {
throw new IllegalArgumentException(name + " cannot be negative");
}
return value;
}
/**
* The underlying data buffer.
*/
private final byte[] data;
/**
* End Of Data.
*
* Similar to data.length, i.e. the last readable offset + 1.
*/
private final int eod;
/**
* Current offset in the data buffer.
*/
private int offset;
/**
* The current mark (if any).
*/
private int markedOffset;
/**
* Constructs a new byte array input stream.
*
* @param data the buffer
* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
*/
@Deprecated
public UnsynchronizedByteArrayInputStream(final byte[] data) {
this(data, data.length, 0, 0);
}
/**
* Constructs a new byte array input stream.
*
* @param data the buffer
* @param offset the offset into the buffer
*
* @throws IllegalArgumentException if the offset is less than zero
* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
*/
@Deprecated
public UnsynchronizedByteArrayInputStream(final byte[] data, final int offset) {
this(data, data.length, Math.min(requireNonNegative(offset, "offset"), minPosLen(data, offset)), minPosLen(data, offset));
}
/**
* Constructs a new byte array input stream.
*
* @param data the buffer
* @param offset the offset into the buffer
* @param length the length of the buffer
*
* @throws IllegalArgumentException if the offset or length less than zero
* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}.
*/
@Deprecated
public UnsynchronizedByteArrayInputStream(final byte[] data, final int offset, final int length) {
requireNonNegative(offset, "offset");
requireNonNegative(length, "length");
this.data = Objects.requireNonNull(data, "data");
this.eod = Math.min(minPosLen(data, offset) + length, data.length);
this.offset = minPosLen(data, offset);
this.markedOffset = minPosLen(data, offset);
}
private UnsynchronizedByteArrayInputStream(final byte[] data, final int eod, final int offset, final int markedOffset) {
this.data = Objects.requireNonNull(data, "data");
this.eod = eod;
this.offset = offset;
this.markedOffset = markedOffset;
}
@Override
public int available() {
return offset < eod ? eod - offset : 0;
}
@SuppressWarnings("sync-override")
@Override
public void mark(final int readLimit) {
this.markedOffset = this.offset;
}
@Override
public boolean markSupported() {
return true;
}
@Override
public int read() {
return offset < eod ? data[offset++] & 0xff : END_OF_STREAM;
}
@Override
public int read(final byte[] dest) {
Objects.requireNonNull(dest, "dest");
return read(dest, 0, dest.length);
}
@Override
public int read(final byte[] dest, final int off, final int len) {
Objects.requireNonNull(dest, "dest");
if (off < 0 || len < 0 || off + len > dest.length) {
throw new IndexOutOfBoundsException();
}
if (offset >= eod) {
return END_OF_STREAM;
}
int actualLen = eod - offset;
if (len < actualLen) {
actualLen = len;
}
if (actualLen <= 0) {
return 0;
}
System.arraycopy(data, offset, dest, off, actualLen);
offset += actualLen;
return actualLen;
}
@SuppressWarnings("sync-override")
@Override
public void reset() {
this.offset = this.markedOffset;
}
@Override
public long skip(final long n) {
if (n < 0) {
throw new IllegalArgumentException("Skipping backward is not supported");
}
long actualSkip = eod - offset;
if (n < actualSkip) {
actualSkip = n;
}
offset = Math.addExact(offset, Math.toIntExact(n));
return actualSkip;
}
}