xmlvm-users

[xmlvm-users] NSData Bug

[Tim C. <ti...@vi...>]

Hi,

I am trying to consume a JSON response, however, NSData byte array size is only 26. I saw there was an earlier discussion about this, but no resolution.

When reviewing the code I see this logic:

	do {
                byte[] buf = new byte[READ_BUF_SIZE];
                i = in.read(buf);

                if (i > 0) {
                    l.add(buf);
                    bytesRead += i;
                }
                
            } while (i == READ_BUF_SIZE);

How is it possible that (i == READ_BUF_SIZE)? In other words read the input stream while i = 32767 - this will end after the first try. I can see that my InputStream does contain all of the data but the readData method only returns a 26 character portion.

I am fixing this for my own immediate needs but in the meantime I wanted to understand if I was missing something since I would assume this to be a fundamental need for a lot of apps???

Here is my fix for the time being:

private void readData(InputStream in) {
        data = new byte[READ_BUF_SIZE];
        
        try {
            int offset = 0;
            int numRead = 0;
            
            while (offset < data.length && (numRead=in.read(data, offset, data.length-offset)) >= 0)
                {
                offset += numRead;
                }

            in.close();
        } catch (IOException ex) {
            // Do nothing
        }
    }

Re: [xmlvm-users] NSData Bug

[Arno P. <ar...@pu...>]

I think that code is correct. If you look at the documentation of 
InputStream.read(byte[]) you will see that if will read at most the 
length of the array. That is that the i == READ_BUF_SIZE is for: it 
indicates that there is potentially more data to be read.

But to mention something else: the code you are referring to is the Java 
implementation of class NSData. This code belongs to XMLVM's Java 
emulator for iOS (meaning you can run a Java-based iOS application on a 
JVM). That was more an experiment and we stopped adding functionality a 
long time ago because we would have to re-implement iOS in Java (which 
is clearly out of scope). Note that that Java implementation you are 
seeing is *not* used during cross-compilation.

Arno


On 3/25/12 10:36 PM, Tim Christensen wrote:
> Hi,
>
> I am trying to consume a JSON response, however, NSData byte array size
> is only 26. I saw there was an earlier discussion about this, but no
> resolution.
>
> When reviewing the code I see this logic:
>
> do {
> byte[] buf = new byte[READ_BUF_SIZE];
> i = in.read(buf);
>
> if (i > 0) {
> l.add(buf);
> bytesRead += i;
> }
>
>
> } while (i == READ_BUF_SIZE);
>
> How is it possible that (i == READ_BUF_SIZE)? In other words read the
> input stream while i = 32767 - this will end after the first try. I can
> see that my InputStream does contain all of the data but the readData
> method only returns a 26 character portion.
>
> I am fixing this for my own immediate needs but in the meantime I wanted
> to understand if I was missing something since I would assume this to be
> a fundamental need for a lot of apps???
>
> Here is my fix for the time being:
>
> private void readData(InputStream in) {
> data= newbyte[READ_BUF_SIZE];
>
>
> try {
> int offset = 0;
> int numRead = 0;
>
>
> while (offset < data.length && (numRead=in.read(data, offset,
> data.length-offset)) >= 0)
> {
> offset += numRead;
> }
>
> in.close();
> } catch (IOException ex) {
> // Do nothing
> }
> }
>
>
>
>
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