I have one int16 variable (2 bytes) and an int32 vaiable(4 bytes). And I want to pack this two variables to js byte array. I can do it so:
<script>
var int16_1 = 10;
var int32_1 = 20;
var buffer = new ArrayBuffer(8);
var buf_1 = new Int16Array(buffer,0,1);
var buf_2 = new Int32Array(buffer,4,1);
buf_1[0]=int16_1;
buf_2[0]=int32_1;
console.log(buffer);
</script>
In this case I have output:
ArrayBuffer(8)
byteLength: 8
[[Prototype]]: ArrayBuffer
[[Int8Array]]: Int8Array(8)
0: 10
1: 0
2: 0 <-extra use byte
3: 0 <-extra use byte
4: 20
5: 0
6: 0
7: 0
But in this case I need to use extra 2 bytes.
If I try to do so:
<script>
var int16_1 = 10;
var int32_1 = 20;
var buffer = new ArrayBuffer(6);
var buf_1 = new Int16Array(buffer,0,1);
var buf_2 = new Int32Array(buffer,2,1);
buf_1[0]=int16_1;
buf_2[0]=int32_1;
console.log(buffer);
</script>
I have an error: Uncaught RangeError: start offset of Int32Array should be a multiple of 4 at new Int32Array ()
If I try to do so:
<script>
var int16_1 = 10;
var int32_1 = 20;
var buffer = new ArrayBuffer(6);
var buf_1 = new Int16Array(buffer,0,1);
var buf_2 = new Int32Array(buffer.slice(2),0,1);
buf_1[0]=int16_1;
buf_2[0]=int32_1;
console.log(buffer);
</script>
I have wrong output:
ArrayBuffer(6)
byteLength: 6
[[Prototype]]: ArrayBuffer
[[Int8Array]]: Int8Array(6)
0: 10
1: 0
2: 0
3: 0
4: 0
5: 0
Is there any way to pack different size data to byte array without extra usage of memory?