I'm trying to read content from a Uri on Android, and I need the final Object type passed to the underlying SDK to by a nio.ByteBuffer.
I can get my hands on an InputStream, via ContentResolver but didn't find a way to wrap it with an nio.ByteBuffer.
Is there a way to convert a Uri content to a nio.ByteBuffer on Android?
I've ended up downloading the content of the Uri locally and open it via other method to get the ByteBuffer
Suppose you are working on an Activity,
private ByteBuffer getByteBuffer(Uri uri){
try{
InputStream iStream = getContentResolver().openInputStream(uri);
if(iStream!=null){
//value of MAX_SIZE is up to your requirement
final int MAX_SIZE = 5000000;
byte[] byteArr = new byte[MAX_SIZE];
int arrSize = 0;
while(true){
int value = iStream.read(byteArr);
if(value == -1){
break;
}else{
arrSize += value;
}
}
iStream.close();
return ByteBuffer.wrap(byteArr, 0, arrSize);
}
}catch(IOException e){
//do something
}
return null;
}
Notes:
(i) InputStream.read(byte[] b) will return an Integer which indicate total number of bytes read into the byte array b at each time.
(ii) If InputStream.read(Byte[] b) returns -1, it indicates that it is the end of the inputStream.
(iii) arrSize stores the total number of bytes read, i.e. the length of byte[] b
(iv) ByteBuffer.wrap(byte[] b, int offset, int length) will wrap the byte array to give a ByteBuffer. You may check this reference
(v) ContentResolver.openInputStream(Uri uri) and InputStream.read(byte[] b) will throw IOException so you must handle it.
(vi) Caution: IndexOutOfBoundException might happen if arrSize > MAX_SIZE, you may need to add if-else clause to handle such issue.
Please feel free to comment or change the code if there is any mistake or if there is a faster way to do that. Happy coding
Related
I am using Cronet API with our current API stack, specifically UploadDataProvider, there is a ByteBuffer with preset limit, seems like the limit size is fixed and we need to pass the data chunk by chunk. Our current API uses InputStream, and write chunk to OutputStream. We're using following code to work with infinite size of file:
byte[] buf = new byte[16 * 1024];
int bytesRead;
while ((bytesRead =inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
I'd like to achieve the same for this Cronet API, UploadDataProvider. My plan was in its read(UploadDataSink, ByteBuffer) method, whenever this read() method was called, read ByteBuffer's limit from inputStream, but my following code not working as expected.
public class MyUploadDataProvider extends UploadDataProvider {
private ReadableByteChannel byteChannel;
MyUploadDataProvider(InputStream inputStream) {
byteChannel = Channels.newChannel(inputStream);
}
#Override
public void read(UploadDataSink uploadDataSink, ByteBuffer byteBuffer) throws IOException {
boolean finalChunk = false;
int read = this.byteChannel.read(byteBuffer);
if (read == -1) {
finalChunk = true;
}
uploadDataSink.onReadSucceeded(finalChunk);
}
}
Not sure why it read failed, can anyone please help me fix this? Thanks!
This is with reference to sipdroid data encrypt failed
I tried using XOR operation instead of reverse byte code for send packets and receive packets in SipdroidSocket.class.
I experienced same issue(too much noise)
Please guide me in encrypting and decrypting packets in SipdroidSocket.class
Sorry for late reply.I am posting the snippets of the code I tried. Please refer the original RtpSocket.java and SipdroidSocket.java classes for complete view. I am just putting the snippets here.
In RtpSocket.java , I took a static value and collected the packet's header length. Then used this header length in SipdroidSocket.java so as to remove the header part prior tweaking with the payload:
In SipdroidSocket.java, following editing were done in Send and Receive functions:
public void receive(DatagramPacket pack) throws IOException {
if (loaded) {
impl.receive(pack);
byte[] b = pack.getData(); // fetch data from receiver
int len = RtpSocket.header;
pack.setData(do_something(b, len)); // do the XORing to retrieve
// original data
} else {
super.receive(pack);
byte[] b = pack.getData();
int len = RtpSocket.header;
pack.setData(do_something(b, len));
}
}
public void send(DatagramPacket pack) throws IOException {
byte[] b = pack.getData(); // fetch original data
int len = RtpSocket.header;
pack.setData(do_something(b, len)); // replace with tweaked data
if (loaded)
impl.send(pack);
else
super.send(pack);
}
private byte[] do_something(byte[] b, int len) {
// TODO Auto-generated method stub
int new_buff_len = b.length - len;
byte[] new_buff = new byte[new_buff_len];
int i = 0;
for (i = len; i < b.length; i++) // separating header values
{
new_buff[i] = (byte) (b[i] ^ 0x43); // XORing original packet
// payload before sending and
// after receiving to get
// original data on both sides
}
return new_buff;
}
Kindly , try it and suggest me please.
Finally it worked ! Had to meddle with the other parts of the code . XOR operation now works fine and have attained the objective.
I am using asyncTask to send images over sockets from Android to PC.
I am calling it like this
new SendImage().execute(data);
where data is of type byte[]
and my code is
private class SendImage extends AsyncTask<byte[],Void, Void> {
#Override
protected Void doInBackground(byte[] ... data) {
try{
final DataOutputStream dataOutputStream;
final BufferedOutputStream out = new BufferedOutputStream(RRAWsecurity.socket.getOutputStream());
int count = data.length;
dataOutputStream = new DataOutputStream(RRAWsecurity.socket.getOutputStream());
dataOutputStream.writeInt(count);
dataOutputStream.flush();
out.write(data, 0, count);
out.flush();
}catch(Exception e)
{
e.printStackTrace();
}
return null;
}
}
The problem is with this line
out.write(data, 0, count);
The error says
The method write(byte[], int, int) in the type BufferedOutputStream is not applicable for the arguments (byte[][], int, int)
I can't figure out why its asking for 2D array ?
Use data[0] instead of data. The ... notation is just some syntactical sugar for an array of the given type. So int... is actually an array of ints and your byte... is treated as an array of byte[] arrays, so it's actually byte[][].
Replace:
int count =data.length; to int count =data[0].length;
out.write(data,0,count); to out.write(data[0],0,count);
data is byte[][]. byte[] ... data is sameas byte[][] data.
Your byte array (byte[]) is one dimentional parameter but BufferedOutputStream's parameter byte[][]) is two dimentional array. Different dimention about array is very big problem. You must convert your array byte to two dimentional array.
All I need is convert byte[] to String. Then do something with that string and convert back to byte[] array. But in this testing I'm just convert byte[] to string and convert back to byte[] and the result is different.
to convert byte[] to string by using this:
byte[] byteEntity = EntityUtils.toByteArray(entity);
String s = new String(byteEntity,"UTF-8");
Then i tried:
byte[] byteTest = s.getBytes("UTF-8");
Then i complared it:
if (byteEntity.equals(byteTest) Log.i("test","equal");
else Log.i("test","diff");
So the result is different.
I searched in stackoverflow about this but it doesn't match my case. The point is my data is .png picture so the string converted is unreadable. Thanks in advance.
Solved
Using something like this.
byte[] mByteEntity = EntityUtils.toByteArray(entity);
byte[] mByteDecrypted = clip_xor(mByteEntity,"your_key".getBytes());
baos.write(mByteDecrypted);
InputStream in = new ByteArrayInputStream(baos.toByteArray());
and this is function clip_xor
protected byte[] clip_xor(byte[] data, byte[] key) {
int num_key = key.length;
int num_data = data.length;
try {
if (num_key > 0) {
for (int i = 0, j = 0; i < num_data; i++, j = (j + 1)
% num_key) {
data[i] ^= key[j];
}
}
} catch (Exception ex) {
Log.i("error", ex.toString());
}
return data;
}
Hope this will useful for someone face same problem. Thanks you your all for helping me solve this.
Special thanks for P'krit_s
primitive arrays are actually Objects (that's why they have .equals method) but they do not implement the contract of equality (hashCode and equals) needed for comparison. You cannot also use == since according to docs, .getBytes will return a new instance byte[]. You should use Arrays.equals(byteEntity, byteTest) to test equality.
Have a look to the answer here.
In that case my target was transform a png image in a bytestream to display it in embedded browser (it was a particular case where browser did not show directly the png).
You may use the logic of that solution to convert png to byte and then to String.
Then reverse the order of operations to get back to the original file.
I have a URL which, when I enter in browser, opens the image perfectly. But when I try the following code, I get getContentLength() as -1:
URL url = new URL(imageUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
// determine the image size and allocate a buffer
int fileSize = connection.getContentLength();
Please guide me what can be the reason behind this?
If the server is sending down the response using Chunked Transfer Encoding, you will not be able to pre-calculate the size. The response is streamed, and you'll just have to allocate a buffer to store the image until the stream is complete. Note that you should only do this if you can guarantee that the image is small enough to fit into memory. Streaming the response to flash storage is a pretty reasonable option if the image may be large.
In-memory solution:
private static final int READ_SIZE = 16384;
byte[] imageBuf;
if (-1 == contentLength) {
byte[] buf = new byte[READ_SIZE];
int bufferLeft = buf.length;
int offset = 0;
int result = 0;
outer: do {
while (bufferLeft > 0) {
result = is.read(buf, offset, bufferLeft);
if (result < 0) {
// we're done
break outer;
}
offset += result;
bufferLeft -= result;
}
// resize
bufferLeft = READ_SIZE;
int newSize = buf.length + READ_SIZE;
byte[] newBuf = new byte[newSize];
System.arraycopy(buf, 0, newBuf, 0, buf.length);
buf = newBuf;
} while (true);
imageBuf = new byte[offset];
System.arraycopy(buf, 0, imageBuf, 0, offset);
} else { // download using the simple method
In theory, if the Http client presents itself as HTTP 1.0, most servers will switch back to non-streaming mode, but I don't believe this is a possibility for URLConnection.
I am late here but this might help someone. I was facing same issue i was always getting -1 value, when ever i was trying get the content length.
previously i was using below method to get content length.
long totalByte=connection.getContentLength();
Below fixed my problem:-
long totalByte=connection.getHeaderFieldLong("Content-Length",-1);