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/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko.util;
import android.util.Log;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Static helper class containing useful methods for manipulating IO objects.
*/
public class IOUtils {
private static final String LOGTAG = "GeckoIOUtils";
/**
* Represents the result of consuming an input stream, holding the returned data as well
* as the length of the data returned.
* The byte[] is not guaranteed to be trimmed to the size of the data acquired from the stream:
* hence the need for the length field. This strategy avoids the need to copy the data into a
* trimmed buffer after consumption.
*/
public static class ConsumedInputStream {
public final int consumedLength;
// Only reassigned in getTruncatedData.
private byte[] consumedData;
public ConsumedInputStream(int consumedLength, byte[] consumedData) {
this.consumedLength = consumedLength;
this.consumedData = consumedData;
}
/**
* Get the data trimmed to the length of the actual payload read, caching the result.
*/
public byte[] getTruncatedData() {
if (consumedData.length == consumedLength) {
return consumedData;
}
consumedData = truncateBytes(consumedData, consumedLength);
return consumedData;
}
public byte[] getData() {
return consumedData;
}
}
/**
* Fully read an InputStream into a byte array.
* @param iStream the InputStream to consume.
* @param bufferSize The initial size of the buffer to allocate. It will be grown as
* needed, but if the caller knows something about the InputStream then
* passing a good value here can improve performance.
*/
public static ConsumedInputStream readFully(InputStream iStream, int bufferSize) {
// Allocate a buffer to hold the raw data downloaded.
byte[] buffer = new byte[bufferSize];
// The offset of the start of the buffer's free space.
int bPointer = 0;
// The quantity of bytes the last call to read yielded.
int lastRead = 0;
try {
// Fully read the data into the buffer.
while (lastRead != -1) {
// Read as many bytes as are currently available into the buffer.
lastRead = iStream.read(buffer, bPointer, buffer.length - bPointer);
bPointer += lastRead;
// If buffer has overflowed, double its size and carry on.
if (bPointer == buffer.length) {
bufferSize *= 2;
byte[] newBuffer = new byte[bufferSize];
// Copy the contents of the old buffer into the new buffer.
System.arraycopy(buffer, 0, newBuffer, 0, buffer.length);
buffer = newBuffer;
}
}
return new ConsumedInputStream(bPointer + 1, buffer);
} catch (IOException e) {
Log.e(LOGTAG, "Error consuming input stream.", e);
} finally {
try {
iStream.close();
} catch (IOException e) {
Log.e(LOGTAG, "Error closing input stream.", e);
}
}
return null;
}
/**
* Truncate a given byte[] to a given length. Returns a new byte[] with the first length many
* bytes of the input.
*/
public static byte[] truncateBytes(byte[] bytes, int length) {
byte[] newBytes = new byte[length];
System.arraycopy(bytes, 0, newBytes, 0, length);
return newBytes;
}
public static void safeStreamClose(Closeable stream) {
try {
if (stream != null)
stream.close();
} catch (IOException e) { }
}
public static void copy(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[4096];
int len;
while ((len = in.read(buffer)) != -1) {
out.write(buffer, 0, len);
}
}
}
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