ooura.js

"use strict";
// pieced together into a single browser-friendly file from https://github.com/audioplastic/ooura

const cftmdl = function (n, l, aBuffer, wBuffer) {
	let j, j1, j2, j3, k, k1, k2;
	let wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
	let x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;

	const a = new Float64Array(aBuffer);
	const w = new Float64Array(wBuffer);

	const m = l << 2;

	for (j = 0; j < l; j += 2) {
		j1 = j + l;
		j2 = j1 + l;
		j3 = j2 + l;
		x0r = a[j] + a[j1];
		x0i = a[j + 1] + a[j1 + 1];
		x1r = a[j] - a[j1];
		x1i = a[j + 1] - a[j1 + 1];
		x2r = a[j2] + a[j3];
		x2i = a[j2 + 1] + a[j3 + 1];
		x3r = a[j2] - a[j3];
		x3i = a[j2 + 1] - a[j3 + 1];
		a[j] = x0r + x2r;
		a[j + 1] = x0i + x2i;
		a[j2] = x0r - x2r;
		a[j2 + 1] = x0i - x2i;
		a[j1] = x1r - x3i;
		a[j1 + 1] = x1i + x3r;
		a[j3] = x1r + x3i;
		a[j3 + 1] = x1i - x3r;
	}

	wk1r = w[2];

	for (j = m; j < l + m; j += 2) {
		j1 = j + l;
		j2 = j1 + l;
		j3 = j2 + l;
		x0r = a[j] + a[j1];
		x0i = a[j + 1] + a[j1 + 1];
		x1r = a[j] - a[j1];
		x1i = a[j + 1] - a[j1 + 1];
		x2r = a[j2] + a[j3];
		x2i = a[j2 + 1] + a[j3 + 1];
		x3r = a[j2] - a[j3];
		x3i = a[j2 + 1] - a[j3 + 1];
		a[j] = x0r + x2r;
		a[j + 1] = x0i + x2i;
		a[j2] = x2i - x0i;
		a[j2 + 1] = x0r - x2r;
		x0r = x1r - x3i;
		x0i = x1i + x3r;
		a[j1] = wk1r * (x0r - x0i);
		a[j1 + 1] = wk1r * (x0r + x0i);
		x0r = x3i + x1r;
		x0i = x3r - x1i;
		a[j3] = wk1r * (x0i - x0r);
		a[j3 + 1] = wk1r * (x0i + x0r);
	}

	k1 = 0;
	const m2 = 2 * m;

	for (k = m2; k < n; k += m2) {
		k1 += 2;
		k2 = 2 * k1;
		wk2r = w[k1];
		wk2i = w[k1 + 1];
		wk1r = w[k2];
		wk1i = w[k2 + 1];
		wk3r = wk1r - 2 * wk2i * wk1i;
		wk3i = 2 * wk2i * wk1r - wk1i;

		for (j = k; j < l + k; j += 2) {
			j1 = j + l;
			j2 = j1 + l;
			j3 = j2 + l;
			x0r = a[j] + a[j1];
			x0i = a[j + 1] + a[j1 + 1];
			x1r = a[j] - a[j1];
			x1i = a[j + 1] - a[j1 + 1];
			x2r = a[j2] + a[j3];
			x2i = a[j2 + 1] + a[j3 + 1];
			x3r = a[j2] - a[j3];
			x3i = a[j2 + 1] - a[j3 + 1];
			a[j] = x0r + x2r;
			a[j + 1] = x0i + x2i;
			x0r -= x2r;
			x0i -= x2i;
			a[j2] = wk2r * x0r - wk2i * x0i;
			a[j2 + 1] = wk2r * x0i + wk2i * x0r;
			x0r = x1r - x3i;
			x0i = x1i + x3r;
			a[j1] = wk1r * x0r - wk1i * x0i;
			a[j1 + 1] = wk1r * x0i + wk1i * x0r;
			x0r = x1r + x3i;
			x0i = x1i - x3r;
			a[j3] = wk3r * x0r - wk3i * x0i;
			a[j3 + 1] = wk3r * x0i + wk3i * x0r;
		}

		wk1r = w[k2 + 2];
		wk1i = w[k2 + 3];
		wk3r = wk1r - 2 * wk2r * wk1i;
		wk3i = 2 * wk2r * wk1r - wk1i;

		for (j = k + m; j < l + (k + m); j += 2) {
			j1 = j + l;
			j2 = j1 + l;
			j3 = j2 + l;
			x0r = a[j] + a[j1];
			x0i = a[j + 1] + a[j1 + 1];
			x1r = a[j] - a[j1];
			x1i = a[j + 1] - a[j1 + 1];
			x2r = a[j2] + a[j3];
			x2i = a[j2 + 1] + a[j3 + 1];
			x3r = a[j2] - a[j3];
			x3i = a[j2 + 1] - a[j3 + 1];
			a[j] = x0r + x2r;
			a[j + 1] = x0i + x2i;
			x0r -= x2r;
			x0i -= x2i;
			a[j2] = -wk2i * x0r - wk2r * x0i;
			a[j2 + 1] = -wk2i * x0i + wk2r * x0r;
			x0r = x1r - x3i;
			x0i = x1i + x3r;
			a[j1] = wk1r * x0r - wk1i * x0i;
			a[j1 + 1] = wk1r * x0i + wk1i * x0r;
			x0r = x1r + x3i;
			x0i = x1i - x3r;
			a[j3] = wk3r * x0r - wk3i * x0i;
			a[j3 + 1] = wk3r * x0i + wk3i * x0r;
		}
	}
};

const cft1st = function (n, aBuffer, wBuffer) {
	let j, k1, k2;
	let wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
	let x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;

	const a = new Float64Array(aBuffer);
	const w = new Float64Array(wBuffer);

	x0r = a[0] + a[2];
	x0i = a[1] + a[3];
	x1r = a[0] - a[2];
	x1i = a[1] - a[3];
	x2r = a[4] + a[6];
	x2i = a[5] + a[7];
	x3r = a[4] - a[6];
	x3i = a[5] - a[7];
	a[0] = x0r + x2r;
	a[1] = x0i + x2i;
	a[4] = x0r - x2r;
	a[5] = x0i - x2i;
	a[2] = x1r - x3i;
	a[3] = x1i + x3r;
	a[6] = x1r + x3i;
	a[7] = x1i - x3r;
	wk1r = w[2];
	x0r = a[8] + a[10];
	x0i = a[9] + a[11];
	x1r = a[8] - a[10];
	x1i = a[9] - a[11];
	x2r = a[12] + a[14];
	x2i = a[13] + a[15];
	x3r = a[12] - a[14];
	x3i = a[13] - a[15];
	a[8] = x0r + x2r;
	a[9] = x0i + x2i;
	a[12] = x2i - x0i;
	a[13] = x0r - x2r;
	x0r = x1r - x3i;
	x0i = x1i + x3r;
	a[10] = wk1r * (x0r - x0i);
	a[11] = wk1r * (x0r + x0i);
	x0r = x3i + x1r;
	x0i = x3r - x1i;
	a[14] = wk1r * (x0i - x0r);
	a[15] = wk1r * (x0i + x0r);
	k1 = 0;

	for (j = 16; j < n; j += 16) {
		k1 += 2;
		k2 = 2 * k1;
		wk2r = w[k1];
		wk2i = w[k1 + 1];
		wk1r = w[k2];
		wk1i = w[k2 + 1];
		wk3r = wk1r - 2 * wk2i * wk1i;
		wk3i = 2 * wk2i * wk1r - wk1i;
		x0r = a[j] + a[j + 2];
		x0i = a[j + 1] + a[j + 3];
		x1r = a[j] - a[j + 2];
		x1i = a[j + 1] - a[j + 3];
		x2r = a[j + 4] + a[j + 6];
		x2i = a[j + 5] + a[j + 7];
		x3r = a[j + 4] - a[j + 6];
		x3i = a[j + 5] - a[j + 7];
		a[j] = x0r + x2r;
		a[j + 1] = x0i + x2i;
		x0r -= x2r;
		x0i -= x2i;
		a[j + 4] = wk2r * x0r - wk2i * x0i;
		a[j + 5] = wk2r * x0i + wk2i * x0r;
		x0r = x1r - x3i;
		x0i = x1i + x3r;
		a[j + 2] = wk1r * x0r - wk1i * x0i;
		a[j + 3] = wk1r * x0i + wk1i * x0r;
		x0r = x1r + x3i;
		x0i = x1i - x3r;
		a[j + 6] = wk3r * x0r - wk3i * x0i;
		a[j + 7] = wk3r * x0i + wk3i * x0r;
		wk1r = w[k2 + 2];
		wk1i = w[k2 + 3];
		wk3r = wk1r - 2 * wk2r * wk1i;
		wk3i = 2 * wk2r * wk1r - wk1i;
		x0r = a[j + 8] + a[j + 10];
		x0i = a[j + 9] + a[j + 11];
		x1r = a[j + 8] - a[j + 10];
		x1i = a[j + 9] - a[j + 11];
		x2r = a[j + 12] + a[j + 14];
		x2i = a[j + 13] + a[j + 15];
		x3r = a[j + 12] - a[j + 14];
		x3i = a[j + 13] - a[j + 15];
		a[j + 8] = x0r + x2r;
		a[j + 9] = x0i + x2i;
		x0r -= x2r;
		x0i -= x2i;
		a[j + 12] = -wk2i * x0r - wk2r * x0i;
		a[j + 13] = -wk2i * x0i + wk2r * x0r;
		x0r = x1r - x3i;
		x0i = x1i + x3r;
		a[j + 10] = wk1r * x0r - wk1i * x0i;
		a[j + 11] = wk1r * x0i + wk1i * x0r;
		x0r = x1r + x3i;
		x0i = x1i - x3r;
		a[j + 14] = wk3r * x0r - wk3i * x0i;
		a[j + 15] = wk3r * x0i + wk3i * x0r;
	}
};

let child = {
	bitrv2: function (n, ipBuffer, ipOffset, aBuffer) {
		let j, j1, k, k1, l, m;
		let xr, xi, yr, yi;

		// Create some views on the raw buffers
		const ip = new Int16Array(ipBuffer).subarray(ipOffset);
		const a = new Float64Array(aBuffer);

		ip[0] = 0;
		l = n;
		m = 1;

		while ((m << 3) < l) {
			l >>= 1;

			for (j = 0; j < m; j++) {
				ip[m + j] = ip[j] + l;
			}

			m <<= 1;
		}

		const m2 = 2 * m;

		if ((m << 3) === l) {
			for (k = 0; k < m; k++) {
				for (j = 0; j < k; j++) {
					j1 = 2 * j + ip[k];
					k1 = 2 * k + ip[j];
					xr = a[j1];
					xi = a[j1 + 1];
					yr = a[k1];
					yi = a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
					j1 += m2;
					k1 += 2 * m2;
					xr = a[j1];
					xi = a[j1 + 1];
					yr = a[k1];
					yi = a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
					j1 += m2;
					k1 -= m2;
					xr = a[j1];
					xi = a[j1 + 1];
					yr = a[k1];
					yi = a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
					j1 += m2;
					k1 += 2 * m2;
					xr = a[j1];
					xi = a[j1 + 1];
					yr = a[k1];
					yi = a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
				}

				j1 = 2 * k + m2 + ip[k];
				k1 = j1 + m2;
				xr = a[j1];
				xi = a[j1 + 1];
				yr = a[k1];
				yi = a[k1 + 1];
				a[j1] = yr;
				a[j1 + 1] = yi;
				a[k1] = xr;
				a[k1 + 1] = xi;
			}
		} else {
			for (k = 1; k < m; k++) {
				for (j = 0; j < k; j++) {
					j1 = 2 * j + ip[k];
					k1 = 2 * k + ip[j];
					xr = a[j1];
					xi = a[j1 + 1];
					yr = a[k1];
					yi = a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
					j1 += m2;
					k1 += m2;
					xr = a[j1];
					xi = a[j1 + 1];
					yr = a[k1];
					yi = a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
				}
			}
		}
	},

	bitrv2conj: function (n, ipBuffer, ipOffset, aBuffer) {
		let j, j1, k, k1, l, m;
		let xr, xi, yr, yi;

		const ip = new Int16Array(ipBuffer).subarray(ipOffset);
		const a = new Float64Array(aBuffer);

		ip[0] = 0;
		l = n;
		m = 1;

		while ((m << 3) < l) {
			l >>= 1;

			for (j = 0; j < m; j++) {
				ip[m + j] = ip[j] + l;
			}

			m <<= 1;
		}

		const m2 = 2 * m;

		if ((m << 3) === l) {
			for (k = 0; k < m; k++) {
				for (j = 0; j < k; j++) {
					j1 = 2 * j + ip[k];
					k1 = 2 * k + ip[j];
					xr = a[j1];
					xi = -a[j1 + 1];
					yr = a[k1];
					yi = -a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
					j1 += m2;
					k1 += 2 * m2;
					xr = a[j1];
					xi = -a[j1 + 1];
					yr = a[k1];
					yi = -a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
					j1 += m2;
					k1 -= m2;
					xr = a[j1];
					xi = -a[j1 + 1];
					yr = a[k1];
					yi = -a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
					j1 += m2;
					k1 += 2 * m2;
					xr = a[j1];
					xi = -a[j1 + 1];
					yr = a[k1];
					yi = -a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
				}

				k1 = 2 * k + ip[k];
				a[k1 + 1] = -a[k1 + 1];
				j1 = k1 + m2;
				k1 = j1 + m2;
				xr = a[j1];
				xi = -a[j1 + 1];
				yr = a[k1];
				yi = -a[k1 + 1];
				a[j1] = yr;
				a[j1 + 1] = yi;
				a[k1] = xr;
				a[k1 + 1] = xi;
				k1 += m2;
				a[k1 + 1] = -a[k1 + 1];
			}
		} else {
			a[1] = -a[1];
			a[m2 + 1] = -a[m2 + 1];

			for (k = 1; k < m; k++) {
				for (j = 0; j < k; j++) {
					j1 = 2 * j + ip[k];
					k1 = 2 * k + ip[j];
					xr = a[j1];
					xi = -a[j1 + 1];
					yr = a[k1];
					yi = -a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
					j1 += m2;
					k1 += m2;
					xr = a[j1];
					xi = -a[j1 + 1];
					yr = a[k1];
					yi = -a[k1 + 1];
					a[j1] = yr;
					a[j1 + 1] = yi;
					a[k1] = xr;
					a[k1 + 1] = xi;
				}

				k1 = 2 * k + ip[k];
				a[k1 + 1] = -a[k1 + 1];
				a[k1 + m2 + 1] = -a[k1 + m2 + 1];
			}
		}
	},

	cftfsub: function (n, aBuffer, wBuffer) {
		let j, j1, j2, j3, l;
		let x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;

		// Create some views on the raw buffers
		const a = new Float64Array(aBuffer);
		const w = new Float64Array(wBuffer);

		l = 2;

		if (n > 8) {
			cft1st(n, a.buffer, w.buffer);
			l = 8;

			while ((l << 2) < n) {
				cftmdl(n, l, a.buffer, w.buffer);
				l <<= 2;
			}
		}

		if ((l << 2) === n) {
			for (j = 0; j < l; j += 2) {
				j1 = j + l;
				j2 = j1 + l;
				j3 = j2 + l;
				x0r = a[j] + a[j1];
				x0i = a[j + 1] + a[j1 + 1];
				x1r = a[j] - a[j1];
				x1i = a[j + 1] - a[j1 + 1];
				x2r = a[j2] + a[j3];
				x2i = a[j2 + 1] + a[j3 + 1];
				x3r = a[j2] - a[j3];
				x3i = a[j2 + 1] - a[j3 + 1];
				a[j] = x0r + x2r;
				a[j + 1] = x0i + x2i;
				a[j2] = x0r - x2r;
				a[j2 + 1] = x0i - x2i;
				a[j1] = x1r - x3i;
				a[j1 + 1] = x1i + x3r;
				a[j3] = x1r + x3i;
				a[j3 + 1] = x1i - x3r;
			}
		} else {
			for (j = 0; j < l; j += 2) {
				j1 = j + l;
				x0r = a[j] - a[j1];
				x0i = a[j + 1] - a[j1 + 1];
				a[j] += a[j1];
				a[j + 1] += a[j1 + 1];
				a[j1] = x0r;
				a[j1 + 1] = x0i;
			}
		}
	},

	cftbsub: function (n, aBuffer, wBuffer) {
		let j, j1, j2, j3, l;
		let x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;

		const a = new Float64Array(aBuffer);
		const w = new Float64Array(wBuffer);

		l = 2;

		if (n > 8) {
			cft1st(n, a.buffer, w.buffer);
			l = 8;

			while ((l << 2) < n) {
				cftmdl(n, l, a.buffer, w.buffer);
				l <<= 2;
			}
		}

		if ((l << 2) === n) {
			for (j = 0; j < l; j += 2) {
				j1 = j + l;
				j2 = j1 + l;
				j3 = j2 + l;
				x0r = a[j] + a[j1];
				x0i = -a[j + 1] - a[j1 + 1];
				x1r = a[j] - a[j1];
				x1i = -a[j + 1] + a[j1 + 1];
				x2r = a[j2] + a[j3];
				x2i = a[j2 + 1] + a[j3 + 1];
				x3r = a[j2] - a[j3];
				x3i = a[j2 + 1] - a[j3 + 1];
				a[j] = x0r + x2r;
				a[j + 1] = x0i - x2i;
				a[j2] = x0r - x2r;
				a[j2 + 1] = x0i + x2i;
				a[j1] = x1r - x3i;
				a[j1 + 1] = x1i - x3r;
				a[j3] = x1r + x3i;
				a[j3 + 1] = x1i + x3r;
			}
		} else {
			for (j = 0; j < l; j += 2) {
				j1 = j + l;
				x0r = a[j] - a[j1];
				x0i = -a[j + 1] + a[j1 + 1];
				a[j] += a[j1];
				a[j + 1] = -a[j + 1] - a[j1 + 1];
				a[j1] = x0r;
				a[j1 + 1] = x0i;
			}
		}
	},

	rftfsub: function (n, aBuffer, nc, cBuffer, cOffset) {
		let j, k, kk;
		let wkr, wki, xr, xi, yr, yi;

		const a = new Float64Array(aBuffer);
		const c = new Float64Array(cBuffer).subarray(cOffset);

		const m = n >> 1;
		const ks = 2 * nc / m;
		kk = 0;

		for (j = 2; j < m; j += 2) {
			k = n - j;
			kk += ks;
			wkr = 0.5 - c[nc - kk];
			wki = c[kk];
			xr = a[j] - a[k];
			xi = a[j + 1] + a[k + 1];
			yr = wkr * xr - wki * xi;
			yi = wkr * xi + wki * xr;
			a[j] -= yr;
			a[j + 1] -= yi;
			a[k] += yr;
			a[k + 1] -= yi;
		}
	},

	rftbsub: function (n, aBuffer, nc, cBuffer, cOffset) {
		let j, k, kk;
		let wkr, wki, xr, xi, yr, yi;

		const a = new Float64Array(aBuffer);
		const c = new Float64Array(cBuffer).subarray(cOffset);

		a[1] = -a[1];
		const m = n >> 1;
		const ks = 2 * nc / m;
		kk = 0;

		for (j = 2; j < m; j += 2) {
			k = n - j;
			kk += ks;
			wkr = 0.5 - c[nc - kk];
			wki = c[kk];
			xr = a[j] - a[k];
			xi = a[j + 1] + a[k + 1];
			yr = wkr * xr + wki * xi;
			yi = wkr * xi - wki * xr;
			a[j] -= yr;
			a[j + 1] = yi - a[j + 1];
			a[k] += yr;
			a[k + 1] = yi - a[k + 1];
		}

		a[m + 1] = -a[m + 1];
	}
};

let _init = {
	makewt: function (nw, ipBuffer, wBuffer) {
		let nwh;
		let delta;
		let x;
		let y;

		const ip = new Int16Array(ipBuffer);
		const w = new Float64Array(wBuffer);

		ip[0] = nw;
		ip[1] = 1;

		if (nw > 2) {
			nwh = nw >> 1;
			delta = Math.atan(1.0) / nwh;
			w[0] = 1;
			w[1] = 0;
			w[nwh] = Math.cos(delta * nwh);
			w[nwh + 1] = w[nwh];

			if (nwh > 2) {
				for (let j = 2; j < nwh; j += 2) {
					x = Math.cos(delta * j);
					y = Math.sin(delta * j);
					w[j] = x;
					w[j + 1] = y;
					w[nw - j] = y;
					w[nw - j + 1] = x;
				}

				child.bitrv2(nw, ip.buffer, 2, w.buffer);
			}
		}
	},

	makect: function (nc, ipBuffer, cBuffer, cOffset) {
		let j;
		let nch;
		let delta;

		const ip = new Int16Array(ipBuffer);
		const c = new Float64Array(cBuffer).subarray(cOffset);

		ip[1] = nc;

		if (nc > 1) {
			nch = nc >> 1;
			delta = Math.atan(1.0) / nch;
			c[0] = Math.cos(delta * nch);
			c[nch] = 0.5 * c[0];

			for (j = 1; j < nch; j++) {
				c[j] = 0.5 * Math.cos(delta * j);
				c[nc - j] = 0.5 * Math.sin(delta * j);
			}
		}
	}
};

const DIRECTION = {
	FORWARDS: +1,
	BACKWARDS: -1
};

let trans = {
	DIRECTION: DIRECTION,
	rdft: function (n, dir, aBuffer, ipBuffer, wBuffer) {
		const ip = new Int16Array(ipBuffer);
		const a = new Float64Array(aBuffer);
		const nw = ip[0];
		const nc = ip[1];

		if (dir === DIRECTION.FORWARDS) {
			if (n > 4) {
				child.bitrv2(n, ipBuffer, 2, aBuffer);
				child.cftfsub(n, aBuffer, wBuffer);
				child.rftfsub(n, aBuffer, nc, wBuffer, nw);
			} else if (n === 4) {
				child.cftfsub(n, aBuffer, wBuffer);
			}

			const xi = a[0] - a[1];
			a[0] += a[1];
			a[1] = xi;
		} else {
			a[1] = 0.5 * (a[0] - a[1]);
			a[0] -= a[1];

			if (n > 4) {
				child.rftbsub(n, aBuffer, nc, wBuffer, nw);
				child.bitrv2(n, ipBuffer, 2, aBuffer);
				child.cftbsub(n, aBuffer, wBuffer);
			} else if (n === 4) {
				child.cftfsub(n, aBuffer, wBuffer);
			}
		}
	},

	cdft: function (n, dir, aBuffer, ipBuffer, wBuffer) {
		if (n > 4) {
			if (dir === DIRECTION.FORWARDS) {
				child.bitrv2(n, ipBuffer, 2, aBuffer);
				child.cftfsub(n, aBuffer, wBuffer);
			} else {
				child.bitrv2conj(n, ipBuffer, 2, aBuffer);
				child.cftbsub(n, aBuffer, wBuffer);
			}
		} else if (n === 4) {
			child.cftfsub(n, aBuffer, wBuffer);
		}
	}
};

class ooura {
	constructor (size, info = {type: 'real', radix: 4}) {
		if (!ooura.isPowerOf2(size)) {
			console.error("Must be a power of 2!");
		}

		this.real = (info.type === 'real');

		if (!this.real) {
			if (info.type !== 'complex') { // Sanity
				console.error("Must be real or complex!");
			}
		}

		this.size = size;
		this.ip = new Int16Array(2 + Math.sqrt(size));
		this.w = new Float64Array(size / 2);
		this.internal = new Float64Array(size);

		_init.makewt(size / 4, this.ip.buffer, this.w.buffer);

		// Perform additional modification if real
		if (this.real) {
			_init.makect(size / 4, this.ip.buffer, this.w.buffer, size / 4);
			this.fft = this.fftReal;
			this.ifft = this.ifftReal;
			this.fftInPlace = this.fftInPlaceReal;
			this.ifftInPlace = this.ifftInPlaceReal;
		} else {
			this.fft = this.fftComplex;
			this.ifft = this.ifftComplex;
			this.fftInPlace = this.fftInPlaceComplex;
			this.ifftInPlace = this.ifftInPlaceComplex;
		}
	}

	// Returns complex vector size given one dimensional scalar size
	static vectorSize (scalarSize) {
		if (!ooura.isPowerOf2(scalarSize)) {
			console.error("Size must be a power of 2!");
		}

		return (scalarSize / 2) + 1;
	}

	// Inverse fucntion of vector size
	static scalarSize (vectorSize) {
		const result = (vectorSize - 1) * 2;

		if (!ooura.isPowerOf2(result)) {
			console.error("Result is not a power of 2!");
		}

		return result;
	}

	static isPowerOf2 (n) {
		if (typeof n !== 'number') {
			return false;
		}

		return n && (n & (n - 1)) === 0;
	}

	getScalarSize () {
		return this.size;
	}

	getVectorSize () {
		return ooura.vectorSize(this.size);
	}

	// Helper factory functions returning correct array and data size for a
	// given fft setup;
	scalarArrayFactory () {
		return new Float64Array(this.getScalarSize());
	}

	vectorArrayFactory () {
		return new Float64Array(this.getVectorSize());
	}

	// Functions below here should be called via their aliases defined in the ctor
	fftReal (dataBuffer, reBuffer, imBuffer) {
		const data = new Float64Array(dataBuffer);
		this.internal.set(data);

		trans.rdft(this.size, trans.DIRECTION.FORWARDS, this.internal.buffer, this.ip.buffer, this.w.buffer);

		const im = new Float64Array(imBuffer);
		const re = new Float64Array(reBuffer);

		// De-interleave data
		let nn = 0;
		let mm = 0;

		while (nn !== this.size) {
			re[nn] = this.internal[mm++];
			im[nn++] = -this.internal[mm++];
		}

		// Post cleanup
		re[this.size / 2] = -im[0];
		im[0] = 0.0;
		im[this.size / 2] = 0.0;
	}

	ifftReal (dataBuffer, reBuffer, imBuffer) {
		const im = new Float64Array(imBuffer);
		const re = new Float64Array(reBuffer);

		// Pack complex into buffer
		let nn = 0;
		let mm = 0;

		while (nn !== this.size) {
			this.internal[mm++] = re[nn];
			this.internal[mm++] = -im[nn++];
		}

		this.internal[1] = re[this.size / 2];

		trans.rdft(this.size, trans.DIRECTION.BACKWARDS, this.internal.buffer, this.ip.buffer, this.w.buffer);

		const data = new Float64Array(dataBuffer);
		data.set(this.internal.map(x => x * 2 / this.size));
	}

	xfftComplex (direction, reIpBuffer, imIpBuffer, reOpBuffer, imOpBuffer) {
		const reIp = new Float64Array(reIpBuffer);
		const imIp = new Float64Array(imIpBuffer);
		const reOp = new Float64Array(reOpBuffer);
		const imOp = new Float64Array(imOpBuffer);

		// Pack complex input into buffer
		let nn = 0;
		let mm = 0;

		while (nn !== this.size) {
			this.internal[mm++] = reIp[nn];
			this.internal[mm++] = -imIp[nn++];
		}

		trans.cdft(this.size, direction, this.internal.buffer, this.ip.buffer, this.w.buffer);

		// De-interleave data into output
		nn = 0;
		mm = 0;

		while (nn !== this.size) {
			reOp[nn] = this.internal[mm++];
			imOp[nn++] = -this.internal[mm++];
		}
	}

	fftComplex (reIpBuffer, imIpBuffer, reOpBuffer, imOpBuffer) {
		this.xfftComplex(trans.DIRECTION.FORWARDS, reIpBuffer, imIpBuffer, reOpBuffer, imOpBuffer);
	}

	ifftComplex (reIpBuffer, imIpBuffer, reOpBuffer, imOpBuffer) {
		this.xfftComplex(trans.DIRECTION.BACKWARDS, reIpBuffer, imIpBuffer, reOpBuffer, imOpBuffer);
		const reOp = new Float64Array(reOpBuffer);
		const imOp = new Float64Array(imOpBuffer);

		for (let nn = 0; nn < this.size / 2; ++nn) {
			reOp[nn] = reOp[nn] * 2 / this.size;
			imOp[nn] = imOp[nn] * 2 / this.size;
		}
	}

	// Below: No-nonsense thin wrappers around the interleaved in-place data
	// representation with no scaling, for maximum throughput.
	fftInPlaceReal (dataBuffer) {
		trans.rdft(this.size, trans.DIRECTION.FORWARDS, dataBuffer, this.ip.buffer, this.w.buffer);
	}

	fftInPlaceComplex (dataBuffer) {
		trans.cdft(this.size, trans.DIRECTION.FORWARDS, dataBuffer, this.ip.buffer, this.w.buffer);
	}

	ifftInPlaceReal (dataBuffer) {
		trans.rdft(this.size, trans.DIRECTION.BACKWARDS, dataBuffer, this.ip.buffer, this.w.buffer);
	}

	ifftInPlaceComplex (dataBuffer) {
		trans.cdft(this.size, trans.DIRECTION.BACKWARDS, dataBuffer, this.ip.buffer, this.w.buffer);
	}

}

/* globals module */

if (typeof module !== "undefined") {
	module.exports = ooura;
}