Roberto De Almeida

To get as close as possible to raw memory from JavaScript we have to use WebGL typed arrays. It’s easy for a JIT to befriend those guys and optimize the hell out of reads and writes, because they have a nice semantics for their backing stores: no nasty holes leading to prototype lookups, all elements have known primitive type and no boxing is required.

var blocks = [];

function Block(size) {
    this.size = size;
    this.buf = new ArrayBuffer(this.size);
    this.i32 = new Int32Array(this.buf);
    this.f64 = new Float64Array(this.buf);
}

function malloc(N) {
    if (blocks[N] && blocks[N].length) return blocks[N].pop();
    return new Block(N);
}

function free(addr) {
    (blocks[addr.size] || (blocks[addr.size] = [])).push(addr);
}

This is a very naïve implementation (I would even say parody) of the famous malloc&free duo. It does not try to optimize memory usage at all but it is perfect for our demonstration.

I need to rewrite my Javascript Opendap server using WebGL typed arrays.