discrepancy between Float32Array and DataView

Question

Thought I understood how Float32Array works, but it looks like I'm not quite there. In the simplest example possible:

buffer = new ArrayBuffer(128);
dataView = new DataView(buffer);
floatArray = new Float32Array(buffer);

dataView.setFloat32(8, 7);
console.log(floatArray[2]); //prints gibberesh

The way I understood it, the data view should set a float starting at the 8th byte to be 7, so the third float in the float array I would expect to be 7.

What am I missing here?

Thanks

You mean `dv.setFloat32(8, 7);` ? – sabof Jul 22 '13 at 03:03 — sabof, Jul 22 '13 at 03:03
oops, fixed typo, also index at 2, not 3 :( – Nick Jul 22 '13 at 03:05 — Nick, Jul 22 '13 at 03:05

sabof · Accepted Answer · 2013-07-22T03:45:40.677

1

This makes it work, the last parameter being littleEndian

dataView.setFloat32(8, 7, true);

This might be better, although I can't say for sure. Presumably Float32Array always uses the system's littleEndian, while DataView can use either.

var littleEndian = (function() {
  var buffer = new ArrayBuffer(2);
  new DataView(buffer).setInt16(0, 256, true);
  return new Int16Array(buffer)[0] === 256;
})();

dataView.setFloat32(8, 7, littleEndian);

edited Jul 22 '13 at 03:45

answered Jul 22 '13 at 03:39

sabof

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huh, funny that they don't both default do doing the same thing. Thanks! – Nick Jul 22 '13 at 04:41
I have the impression *Array was meant for computations, and DataView for binary files. – sabof Jul 22 '13 at 05:00

discrepancy between Float32Array and DataView

1 Answers1