minio/mint/build/aws-sdk-java/src/LimitedInputStream.java

/*
 * Copyright (c) 2015-2021 MinIO, Inc.
 *
 * This file is part of MinIO Object Storage stack
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package io.minio.awssdk.tests;

import java.io.*;

// LimitedInputStream wraps a regular InputStream, calling
// read() will skip some bytes as configured and will also
// return only data with configured length

class LimitedInputStream extends InputStream {

    private int skip;
    private int length;
    private InputStream is;

    LimitedInputStream(InputStream is, int skip, int length) {
        this.is = is;
        this.skip = skip;
        this.length = length;
    }

    @Override
    public int read() throws IOException {
        int r;
        while (skip > 0) {
            r = is.read();
            if (r < 0) {
                throw new IOException("stream ended before being able to skip all bytes");
            }
            skip--;
        }
        if (length == 0) {
            return -1;
        }
        r = is.read();
        if (r < 0) {
            throw new IOException("stream ended before being able to read all bytes");
        }
        length--;
        return r;
    }
}