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package com.sap.it.commons.tools;

import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.logging.Level;
import java.util.logging.Logger;

public class IoTools {
    private static final String LOGGER_NAME = IoTools.class.getName();

    private static final int DEFAULT_BLOCK_SIZE = 1024 * 4;

    public static final OutputStream NULL_OUTPUT_STREAM = new OutputStream() {
        @Override
        public void write(int b) {
        }

        @Override
        public void write(byte[] b, int off, int len) {
        }

        @Override
        public void write(byte[] b) {
        }
    };

    private IoTools() {
    }

    public static IOException closeConsumeException(Closeable closeable, String details) {
        try {
            close(closeable);
            return null;
        } catch (IOException e) {
            Logger.getLogger(LOGGER_NAME).log(Level.WARNING, "Failed to close {0}", details != null ? details : closeable.toString());
            return e;
        }
    }

    public static IOException closeConsumeException(Closeable closeable) {
        return closeConsumeException(closeable, null);
    }

    public static void close(Closeable closeable) throws IOException {
        if (closeable != null) {
            closeable.close();
        }
    }

    /**
     * Copies InputStream to OutputStream up to a specified amount of bytes.
     * 
     * @param is
     *            the InputStream
     * @param os
     *            the OutputStream
     * @param max
     *            maximum number of bytes to be copied
     * @return number of copied bytes
     * @throws IOException
     */
    public static long copy(InputStream is, OutputStream os, long max) throws IOException {
        byte[] buff = new byte[DEFAULT_BLOCK_SIZE];
        int count = 0;
        long total = 0;
        int len = (int) Math.min(max, (long) DEFAULT_BLOCK_SIZE);
        while (len > 0 && (count = is.read(buff, 0, len)) > 0) {
            os.write(buff, 0, count);
            total += count;
            len = (int) Math.min(max - total, (long) DEFAULT_BLOCK_SIZE);
        }
        return total;
    }

    public static long copy(InputStream is, OutputStream os) throws IOException {
        byte[] buff = new byte[DEFAULT_BLOCK_SIZE];
        int count = 0;
        long total = 0;
        while ((count = is.read(buff)) > 0) {
            os.write(buff, 0, count);
            total += count;
        }
        return total;
    }

    public static long consume(InputStream is) throws IOException {
        return copy(is, NULL_OUTPUT_STREAM);
    }

}