org.brewchain.sdk.contract.rlp.RLPStreamIterator Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of cwvj Show documentation
Java sdk for Dapps interact with cwv blockchain node
There is a newer version: 2.2.1
/*
   Copyright 2019 Evan Saulpaugh

   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 org.brewchain.sdk.contract.rlp;

import org.brewchain.sdk.contract.rlp.exception.DecodeException;
import org.brewchain.sdk.contract.rlp.exception.UnrecoverableDecodeException;

import java.io.IOException;
import java.io.InputStream;
import java.util.NoSuchElementException;

public class RLPStreamIterator implements AutoCloseable {

    private final RLPDecoder decoder;
    private final InputStream rlpStream;

    private byte[] buffer;
    private int index;

    private RLPItem rlpItem;

    RLPStreamIterator(RLPDecoder decoder, InputStream rlpStream) {
        this.decoder = decoder;
        this.rlpStream = rlpStream;
        this.buffer = new byte[this.index = 0]; // make sure index == buffer.length
    }

    public boolean hasNext() throws IOException, UnrecoverableDecodeException {
        if (rlpItem != null) {
            return true;
        }
        final int available = rlpStream.available();
        if (available > 0) {
            int keptBytes = buffer.length - index;
            byte[] newBuffer = new byte[keptBytes + available];
            System.arraycopy(buffer, index, newBuffer, 0, keptBytes);
            buffer = newBuffer;
            index = 0;
            int read = rlpStream.read(buffer, keptBytes, available);
            if (read != available) {
                throw new IOException("read failed: " + read + " != " + available);
            }
        }
        if (index == buffer.length) {
            return false;
        }
        try {
            rlpItem = decoder.wrap(buffer, index);
            return true;
        } catch (DecodeException e) {
            if (e.isRecoverable()) {
                return false;
            }
            throw (UnrecoverableDecodeException) e;
        }
    }

    public RLPItem next() throws IOException, UnrecoverableDecodeException {
        if(hasNext()) {
            index = rlpItem.endIndex;
            RLPItem item = rlpItem;
            rlpItem = null;
            return item;
        }
        throw new NoSuchElementException();
    }

    @Override
    public void close() throws IOException {
        rlpStream.close();
    }
}