How to read a struct from a JS ArrayBuffer efficiently (browser)?

Question

Let's say I have a struct of the form

typedef struct {
  uint32_t intensity;
  uint16_t ring;
  float32_t x;
  float32_t y;
  float32_t z;
} Point;

(18 bytes total) and I have a huge array of several tens of thousands of these 18-byte structs in an ArrayBuffer.

How do I iterate through them efficiently without calling a "new DataView()" constructor irritatively in a loop?

This is in the browser, not NodeJS.

georg · Accepted Answer · 2021-07-16 10:13:27Z

6

There's no need to create a new DataView each time you read a value. Create it just once and use offset to read data at the specific location:

let dv = new DataView(buffer);
let offset = 0;

while (offset < buffer.byteLength) {
    intensity = dv.getUint32(offset);  offset += 32;
    ring = dv.getUint16(offset);       offset += 16;
    // etc
}

}

answered Jul 16, 2021 at 10:13

georg

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1 Comment

grzegorz Over a year ago

Offset is in bytes so it should be offset += 4; and offset += 2;.

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