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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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
 *
 *     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 com.aliyun.datahub.common.util;

import java.io.*;

/**
 * IO Utils
 */
public class IOUtils {

    public static final int READ_BUFFER_SIZE = 4096;

    private static final int EOF = -1;

    /**
     * Read fully from the InputStream
     *
     * @param in
     * @return
     * @throws IOException
     */
    public static byte[] readFully(InputStream in) throws IOException {
        try {
            byte[] buf = new byte[READ_BUFFER_SIZE];
            int read = -1;
            ByteArrayOutputStream os = new ByteArrayOutputStream();
            while ((read = in.read(buf)) != -1) {
                os.write(buf, 0, read);
            }
            os.close();
            return os.toByteArray();
        } finally {
            if (in != null) {
                in.close();
            }
        }
    }

    /**
     * Get InputStream bytes count without reading
     *
     * @param in
     * @return
     * @throws IOException
     */
    public static long getInputStreamLength(InputStream in) throws IOException {
        if (in instanceof FileInputStream) {
            return ((FileInputStream) in).getChannel().size();
        }
        return in.available();
    }

    /**
     * Reset the InputStream to the beginning/mark position without a large buffer
     *
     * @param in
     * @throws IOException
     */
    public static void resetInputStream(InputStream in) throws IOException {
        if (in.markSupported()) {
            in.reset();
        }
        if (in instanceof FileInputStream) {
            ((FileInputStream) in).getChannel().position(0);
        }
    }

    /**
     * Copy bytes from a large (over 2GB) InputStream to an
     * OutputStream.
     * 
     * This method buffers the input internally, so there is no need to use a
     * BufferedInputStream.
     * 
     * The buffer size is given by  #DEFAULT_BUFFER_SIZE}.
     *
     * @param input  the InputStream to read from
     * @param output the OutputStream to write to
     * @return the number of bytes copied
     * @throws NullPointerException if the input or output is null
     * @throws IOException          if an I/O error occurs
     * @since Shamelessly cloned from Apache Commons IO 1.3 IOUtils
     */
    public static long copyLarge(InputStream input, OutputStream output) throws IOException {
        return copyLarge(input, output, new byte[READ_BUFFER_SIZE]);
    }

    /**
     * Copy bytes from a large (over 2GB) InputStream to an
     * OutputStream.
     * 
     * This method uses the provided buffer, so there is no need to use a
     * BufferedInputStream.
     * 
     *
     * @param input  the InputStream to read from
     * @param output the OutputStream to write to
     * @param buffer the buffer to use for the copy
     * @return the number of bytes copied
     * @throws NullPointerException if the input or output is null
     * @throws IOException          if an I/O error occurs
     * @since Shamelessly cloned from Apache Commons IO 2.2 IOUtils
     */
    public static long copyLarge(InputStream input, OutputStream output, byte[] buffer)
            throws IOException {
        long count = 0;
        int n = 0;
        while (EOF != (n = input.read(buffer))) {
            output.write(buffer, 0, n);
            count += n;
        }
        return count;
    }

    public static String readStreamAsString(InputStream in, String charset) throws IOException {
        return new String(readFully(in), charset);
    }

    public static String readStreamAsString(InputStream in) throws IOException {
        return new String(readFully(in), "utf-8");
    }
}