Use PHP to Decode BASE64 encoded Signed Integers in 16bit

Question

I have a Base64 encoded string and I am using the following c# code to decode it. Inside should be a range of Signed integers stored in 16bit.

Now I need to do it in PHP but I'm having real trouble. Can anyone help?

Basically can anyone convert this code to php?

    private string decode(string encoded) 
    {
        Byte[] newBytes = Convert.FromBase64String(
            encoded.Replace("\n","")
        );

        int[] newArr = new int[newBytes.Length / 4];
        for (int ctr = 0; ctr < newBytes.Length / 4; ctr++)
            newArr[ctr] = BitConverter.ToInt16(newBytes, ctr * 4);

        return DisplayArray(newArr);
    }

    private string DisplayArray(Array arr)
    {
        string output = "";
        for (int ctr = 0; ctr < arr.GetUpperBound(0); ctr++)
        {
            output += arr.GetValue(ctr)  + ",";
        }

        return output;      
    }

Here is the base64 string....
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and it should decode to...

2,0,0,2,2,2,2,2,2,5,5,5,2,0,0,7,5,5,0,0,0,2,5,5,2,2,0,0,0,2,0,2,5,2,2,2,2,5,2,2,5,5,0,5,2,2,0,5,5,0,2,0,2,2,5,7,5,2,0,2,2,2,2,5,5,2,0,2,2,5,0,-2,2,2,0,2,0,5,5,0,2,2,2,0,0,2,2,2,5,2,5,7,5,5,5,7,7,5,7,7,5,7,7,7,5,2,-2,2,2,5,5,2,2,2,7,2,5,5,0,7,2,5,0,2,2,7,5,2,2,2,7,7,7,7,5,2,5,5,5,10,10,7,10,10,10,12,12,12,17,15,20,20,20,22,17,20,20,22,25,27,27,27,32,35,40,40,40,40,40,37,37,37,40,42,37,35,30,35,25,25,20,15,10,7,2,7,5,2,2,0,0,-2,0,2,-2,0,5,2,0,5,0,0,0,-2,0,-2,0,-2,-2,-5,-2,0,-5,-2,-2, etc...

Answer 1

The good

PHP makes it really easy to read in base64 data and convert it to an array of signed integers. Make sure to read up on the unpack function, it's great.

$stringValue = base64_decode($base64data, true);
$integers = unpack("s*", $stringValue);

---

The bad

That is not what your C# code is doing. After converting the base64 into raw bytes, it then processes that data in chunks of 4 bytes, parsing the first 2 into an int16 and throwing away the second two bytes. Half your data goes down the drain.

---

The ugly

If the C# code is really the algorithm you are after, here is how to do it in PHP:

$stringValue = base64_decode($base64data, true);
$integers = unpack("s*", $stringValue);
// Throw away half of our data. Because... why not? :)
$integers = array_map('array_shift', array_chunk($integers, 2));