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import java.io.*;
import java.net.*;
import java.util.*;
class Download: Runnable {
public enum class Status {
DOWNLOADING, PAUSED, COMPLETE, CANCELLED, ERROR
}
public var size: Int
public var downloaded: Int
public var contentLength: Int
public var status: Status
private final val MAX_BUFFER_SIZE: Number = 1024
private var url: URL
constructor (url: URL) {
this.url = url
size = -1
downloaded = 0
status = Status.DOWNLOADING
contentLength = 1
}
public fun start() {
val thread = Thread(this)
thread.start()
}
private fun getFilename(url: URL): String {
val filename = url.getFile()
return filename.substring(filename.lastIndexOf('/') + 1)
}
override fun run() {
var stream: InputStream? = null
var file: RandomAccessFile? = null
try {
// Open connection to URL.
var connection = url.openConnection() as HttpURLConnection;
// Specify what portion of file to download.
connection.setRequestProperty("Range", "bytes=" + downloaded + "-");
// Connect to server.
connection.connect();
// Make sure response code is in the 200 range.
if (connection.responseCode / 100 != 2) {
status = Status.ERROR
}
// Check for valid content length.
contentLength = connection.getContentLength();
if (contentLength < 1) {
status = Status.ERROR
}
/* Set the size for this download if it
hasn't been already set. */
if (size == -1) {
size = contentLength;
}
// Open file and seek to the end of it.
file = RandomAccessFile(getFilename(url), "rw");
file.seek(downloaded.toLong());
stream = connection.getInputStream();
while (status == Status.DOWNLOADING) {
/* Size buffer according to how much of the
file is left to download. */
val buffer: ByteArray;
if (size - downloaded > MAX_BUFFER_SIZE as Int) {
buffer = ByteArray(MAX_BUFFER_SIZE)
} else {
buffer = ByteArray(size - downloaded);
}
// Read from server into buffer.
val read = stream.read(buffer);
if (read == -1)
break;
// Write buffer to file.
file.write(buffer, 0, read);
downloaded += read;
}
/* Change status to complete if this point was
reached because downloading has finished. */
if (status == Status.DOWNLOADING) {
status = Status.COMPLETE;
}
} catch (e: Exception) {
status = Status.ERROR
} finally {
// Close file.
if (file != null) {
try {
file.close();
} catch (e: Exception) {}
}
// Close connection to server.
if (stream != null) {
try {
stream.close();
} catch (e: Exception) {}
}
}
}
}
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