Android Open Source - base-android-utils Io Utils

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/*******************************************************************************
 * Copyright 2011-2014 Sergey Tarasevich
 */*  ww  w.j a v  a2 s. co  m*/
 * 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 me.pc.mobile.helper.v14.util;

import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Provides I/O operations
 *
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 * @since 1.0.0
 */
public final class IoUtils {

  /** {@value} */
  public static final int DEFAULT_BUFFER_SIZE = 32 * 1024; // 32 KB
  /** {@value} */
  public static final int DEFAULT_IMAGE_TOTAL_SIZE = 500 * 1024; // 500 Kb
  /** {@value} */
  public static final int CONTINUE_LOADING_PERCENTAGE = 75;

  private IoUtils() {
  }

  /**
   * Copies stream, fires progress events by listener, can be interrupted by listener. Uses buffer size =
   * {@value #DEFAULT_BUFFER_SIZE} bytes.
   *
   * @param is       Input stream
   * @param os       Output stream
   * @param listener null-ok; Listener of copying progress and controller of copying interrupting
   * @return <b>true</b> - if stream copied successfully; <b>false</b> - if copying was interrupted by listener
   * @throws IOException
   */
  public static boolean copyStream(InputStream is, OutputStream os, CopyListener listener) throws IOException {
    return copyStream(is, os, listener, DEFAULT_BUFFER_SIZE);
  }

  /**
   * Copies stream, fires progress events by listener, can be interrupted by listener.
   *
   * @param is         Input stream
   * @param os         Output stream
   * @param listener   null-ok; Listener of copying progress and controller of copying interrupting
   * @param bufferSize Buffer size for copying, also represents a step for firing progress listener callback, i.e.
   *                   progress event will be fired after every copied <b>bufferSize</b> bytes
   * @return <b>true</b> - if stream copied successfully; <b>false</b> - if copying was interrupted by listener
   * @throws IOException
   */
  public static boolean copyStream(InputStream is, OutputStream os, CopyListener listener, int bufferSize)
      throws IOException {
    int current = 0;
    int total = is.available();
    if (total <= 0) {
      total = DEFAULT_IMAGE_TOTAL_SIZE;
    }

    final byte[] bytes = new byte[bufferSize];
    int count;
    if (shouldStopLoading(listener, current, total)) return false;
    while ((count = is.read(bytes, 0, bufferSize)) != -1) {
      os.write(bytes, 0, count);
      current += count;
      if (shouldStopLoading(listener, current, total)) return false;
    }
    os.flush();
    return true;
  }

  private static boolean shouldStopLoading(CopyListener listener, int current, int total) {
    if (listener != null) {
      boolean shouldContinue = listener.onBytesCopied(current, total);
      if (!shouldContinue) {
        if (100 * current / total < CONTINUE_LOADING_PERCENTAGE) {
          return true; // if loaded more than 75% then continue loading anyway
        }
      }
    }
    return false;
  }

  /**
   * Reads all data from stream and close it silently
   *
   * @param is Input stream
   */
  public static void readAndCloseStream(InputStream is) {
    final byte[] bytes = new byte[DEFAULT_BUFFER_SIZE];
    try {
      while (is.read(bytes, 0, DEFAULT_BUFFER_SIZE) != -1);
    } catch (IOException ignored) {
    } finally {
      closeSilently(is);
    }
  }

  public static void closeSilently(Closeable closeable) {
    if (closeable != null) {
      try {
        closeable.close();
      } catch (Exception ignored) {
      }
    }
  }

  /** Listener and controller for copy process */
  public static interface CopyListener {
    /**
     * @param current Loaded bytes
     * @param total   Total bytes for loading
     * @return <b>true</b> - if copying should be continued; <b>false</b> - if copying should be interrupted
     */
    boolean onBytesCopied(int current, int total);
  }
}

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