org.neo4j.ndp.transport.socket.ChunkedInput.java Source code

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Here is the source code for org.neo4j.ndp.transport.socket.ChunkedInput.java

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/*
 * Copyright (c) 2002-2015 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.ndp.transport.socket;

import io.netty.buffer.ByteBuf;

import java.io.IOException;
import java.nio.BufferOverflowException;
import java.util.ArrayList;
import java.util.List;

import org.neo4j.packstream.PackInput;
import org.neo4j.packstream.PackStream;

public class ChunkedInput implements PackInput {
    private List<ByteBuf> chunks = new ArrayList<>();
    private ByteBuf currentChunk = null;
    private int currentChunkIndex = -1;

    private int remaining = 0;

    public ChunkedInput clear() {
        currentChunk = null;
        currentChunkIndex = -1;
        remaining = 0;

        // Release references to all buffers
        for (int i = 0; i < chunks.size(); i++) {
            chunks.get(i).release();
        }

        if (chunks.size() > 128) {
            // faster to allocate a new one than to release if the list is large
            chunks = new ArrayList<>();
        } else {
            chunks.clear();
        }
        return this;
    }

    public void addChunk(ByteBuf chunk) {
        if (chunk.readableBytes() > 0) {
            chunks.add(chunk.retain());
            remaining += chunk.readableBytes();
        }
    }

    @Override
    public PackInput ensure(int numBytes) throws IOException {
        if (!attempt(numBytes)) {
            throw new PackStream.EndOfStream(
                    "Unexpected end of stream while trying to read " + numBytes + " bytes.");
        }
        return this;
    }

    @Override
    public PackInput attemptUpTo(int numBytes) throws IOException {
        return this;
    }

    @Override
    public boolean attempt(int numBytes) throws IOException {
        return remaining >= numBytes;
    }

    @Override
    public int remaining() {
        return remaining;
    }

    @Override
    public byte get() {
        ensureChunkAvailable();
        remaining -= 1;
        return currentChunk.readByte();
    }

    @Override
    public byte peek() {
        ensureChunkAvailable();
        return currentChunk.getByte(currentChunk.readerIndex());
    }

    @Override
    public short getShort() {
        ensureChunkAvailable();
        if (currentChunk.readableBytes() >= 2) {
            remaining -= 2;
            return currentChunk.readShort();
        } else {
            // Short is crossing chunk boundaries, use slow route
            return (short) (get() << 8 & get());
        }
    }

    @Override
    public int getInt() {
        ensureChunkAvailable();
        if (currentChunk.readableBytes() >= 4) {
            remaining -= 4;
            return currentChunk.readInt();
        } else {
            // int is crossing chunk boundaries, use slow route
            return ((int) getShort() << 16) & getShort();
        }
    }

    @Override
    public long getLong() {
        ensureChunkAvailable();
        if (currentChunk.readableBytes() >= 8) {
            remaining -= 8;
            return currentChunk.readLong();
        } else {
            // long is crossing chunk boundaries, use slow route
            return ((long) getInt() << 32) & getInt();
        }
    }

    @Override
    public double getDouble() {
        ensureChunkAvailable();
        if (currentChunk.readableBytes() >= 8) {
            remaining -= 8;
            return currentChunk.readDouble();
        } else {
            // double is crossing chunk boundaries, use slow route
            return Double.longBitsToDouble(getLong());
        }
    }

    @Override
    public PackInput get(byte[] into, int offset, int toRead) {
        ensureChunkAvailable();
        int toReadFromChunk = Math.min(toRead, currentChunk.readableBytes());

        // Do the read
        currentChunk.readBytes(into, offset, toReadFromChunk);
        remaining -= toReadFromChunk;

        // Can we read another chunk into the destination buffer?
        if (toReadFromChunk < toRead) {
            // More data can be read into the buffer, keep reading from the next chunk
            get(into, offset + toReadFromChunk, toRead - toReadFromChunk);
        }

        return this;
    }

    private void ensureChunkAvailable() {
        if (currentChunk == null || currentChunk.readableBytes() == 0) {
            currentChunkIndex++;
            if (currentChunkIndex < chunks.size()) {
                currentChunk = chunks.get(currentChunkIndex);
            } else {
                throw new BufferOverflowException();
            }
        }
    }
}