/*******************************************************************************
* Copyright 2011-2013 Sergey Tarasevich
*
* 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 com.smartandroid.sa.zUImageLoader.utils;
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 e) {
// Do nothing
} finally {
closeSilently(is);
}
}
public static void closeSilently(Closeable closeable) {
try {
closeable.close();
} catch (Exception e) {
// Do nothing
}
}
/** 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);
}
}