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/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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:
 *
 *   https://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 io.netty5.handler.stream;

import io.netty5.buffer.Buffer;
import io.netty5.buffer.BufferAllocator;

import java.io.InputStream;
import java.io.PushbackInputStream;

import static java.util.Objects.requireNonNull;

/**
 * A {@link ChunkedInput} that fetches data from an {@link InputStream} chunk by
 * chunk.
 * 

* Please note that the {@link InputStream} instance that feeds data into * {@link ChunkedStream} must implement {@link InputStream#available()} as * accurately as possible, rather than using the default implementation. * Otherwise, {@link ChunkedStream} will generate many too small chunks or * block unnecessarily often. */ public class ChunkedStream implements ChunkedInput { static final int DEFAULT_CHUNK_SIZE = 8192; private final PushbackInputStream in; private final int chunkSize; private long offset; private boolean closed; private byte[] cachedArray; /** * Creates a new instance that fetches data from the specified stream. */ public ChunkedStream(InputStream in) { this(in, DEFAULT_CHUNK_SIZE); } /** * Creates a new instance that fetches data from the specified stream. * * @param chunkSize the number of bytes to fetch on each {@link #readChunk(BufferAllocator)} call. */ public ChunkedStream(InputStream in, int chunkSize) { requireNonNull(in, "in"); if (chunkSize <= 0) { throw new IllegalArgumentException( "chunkSize: " + chunkSize + " (expected: a positive integer)"); } if (in instanceof PushbackInputStream) { this.in = (PushbackInputStream) in; } else { this.in = new PushbackInputStream(in); } this.chunkSize = chunkSize; } /** * Returns the number of transferred bytes. */ public long transferredBytes() { return offset; } @Override public boolean isEndOfInput() throws Exception { if (closed) { return true; } if (in.available() > 0) { return false; } int b = in.read(); if (b < 0) { return true; } else { in.unread(b); return false; } } @Override public void close() throws Exception { closed = true; in.close(); } @Override public Buffer readChunk(BufferAllocator allocator) throws Exception { if (isEndOfInput()) { return null; } final int availableBytes = in.available(); final int chunkSize; if (availableBytes <= 0) { chunkSize = this.chunkSize; } else { chunkSize = Math.min(this.chunkSize, in.available()); } boolean release = true; Buffer buffer = allocator.allocate(chunkSize); try { // transfer to buffer int written; try (var iter = buffer.forEachComponent()) { var component = iter.firstWritable(); if (component.hasWritableArray()) { written = in.read(component.writableArray(), component.writableArrayOffset(), component.writableArrayLength()); } else { int size = Math.min(component.writableBytes(), chunkSize); if (cachedArray == null || cachedArray.length < size) { cachedArray = new byte[size]; } written = in.read(cachedArray, 0, size); if (written > 0) { buffer.writeBytes(cachedArray, 0, written); } } } if (written < 0) { return null; } offset += written; release = false; return buffer; } finally { if (release) { buffer.close(); } } } @Override public long length() { return -1; } @Override public long progress() { return offset; } }





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