net.dongliu.cute.http.body.AggregateInputStream Maven / Gradle / Ivy

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package net.dongliu.cute.http.body;

import net.dongliu.commons.io.Closeables;

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

/**
 * InputStream that merge multi InputStreams.
 */
class AggregateInputStream extends InputStream {
    private InputStream[] inputStreams;
    private int index;

    public AggregateInputStream(InputStream... inputStreams) {
        this.inputStreams = inputStreams;
    }

    public AggregateInputStream(List inputStreams) {
        this.inputStreams = inputStreams.toArray(InputStream[]::new);
    }

    @Override
    public synchronized int read(byte[] b) throws IOException {
        if (EOF()) {
            return -1;
        }
        do {
            int count;
            if ((count = current().read(b)) >= 0) {
                return count;
            }
        } while (next());
        return -1;
    }

    @Override
    public synchronized int read(byte[] b, int off, int len) throws IOException {
        if (EOF()) {
            return -1;
        }
        do {
            int count;
            if ((count = current().read(b, off, len)) >= 0) {
                return count;
            }
        } while (next());
        return -1;
    }

    @Override
    public synchronized long skip(long n) throws IOException {
        if (EOF()) {
            return 0;
        }
        return current().skip(n);
    }

    @Override
    public synchronized int available() throws IOException {
        if (EOF()) {
            return 0;
        }
        return current().available();
    }

    @Override
    public synchronized int read() throws IOException {
        if (EOF()) {
            return -1;
        }
        do {
            int value;
            if ((value = current().read()) >= 0) {
                return value;
            }
        } while (next());
        return -1;
    }

    @Override
    public synchronized void close() throws IOException {
        for (var in : inputStreams) {
            Closeables.closeQuietly(in);
        }
    }

    /*
     * Delegate to next inputStream.
     * return false if no more stream
     */
    private boolean next() {
        if (index >= inputStreams.length - 1) {
            return false;
        }
        Closeables.closeQuietly(inputStreams[index]);
        index++;
        return true;
    }

    /*
     * Current inputStream delegated to .
     */
    private InputStream current() {
        return inputStreams[index];
    }

    private boolean EOF() {
        return index >= inputStreams.length;
    }
}