plugins/FFTPlugin.js

/* Smalltalk from Squeak4.5 with VMMaker 4.13.6 translated as JS source on 3 November 2014 1:52:20 pm */
/* Automatically generated by
	JSPluginCodeGenerator VMMakerJS-bf.15 uuid: fd4e10f2-3773-4e80-8bb5-c4b471a014e5
   from
	FFTPlugin VMMaker-bf.353 uuid: 8ae25e7e-8d2c-451e-8277-598b30e9c002
 */

(function FFTPlugin() {
"use strict";

var VM_PROXY_MAJOR = 1;
var VM_PROXY_MINOR = 11;

/*** Functions ***/
function CLASSOF(obj) { return typeof obj === "number" ? interpreterProxy.classSmallInteger() : obj.sqClass }
function SIZEOF(obj) { return obj.pointers ? obj.pointers.length : obj.words ? obj.words.length : obj.bytes ? obj.bytes.length : 0 }
function BYTESIZEOF(obj) { return obj.bytes ? obj.bytes.length : obj.words ? obj.words.length * 4 : 0 }
function DIV(a, b) { return Math.floor(a / b) | 0; }   // integer division
function MOD(a, b) { return a - DIV(a, b) * b | 0; }   // signed modulus
function SHL(a, b) { return b > 31 ? 0 : a << b; }     // fix JS shift
function SHR(a, b) { return b > 31 ? 0 : a >>> b; }    // fix JS shift
function SHIFT(a, b) { return b < 0 ? (b < -31 ? 0 : a >>> (0-b) ) : (b > 31 ? 0 : a << b); }

/*** Variables ***/
var fftSize = 0;
var imagData = null;
var imagDataSize = 0;
var interpreterProxy = null;
var moduleName = "FFTPlugin 3 November 2014 (e)";
var nu = 0;
var permTable = null;
var permTableSize = 0;
var realData = null;
var realDataSize = 0;
var sinTable = null;
var sinTableSize = 0;



/*	Return the first indexable word of oop which is assumed to be variableWordSubclass */

function checkedFloatPtrOf(oop) {
	interpreterProxy.success(interpreterProxy.isWords(oop));
	if (interpreterProxy.failed()) {
		return 0;
	}
	return oop.wordsAsFloat32Array();
}


/*	Return the first indexable word of oop which is assumed to be variableWordSubclass */

function checkedWordPtrOf(oop) {
	interpreterProxy.success(interpreterProxy.isWords(oop));
	return oop.words;
}


/*	Note: This is hardcoded so it can be run from Squeak.
	The module name is used for validating a module *after*
	it is loaded to check if it does really contain the module
	we're thinking it contains. This is important! */

function getModuleName() {
	return moduleName;
}

function halt() {
	;
}

function loadFFTFrom(fftOop) {
	var oop;

	interpreterProxy.success(SIZEOF(fftOop) >= 6);
	if (interpreterProxy.failed()) {
		return false;
	}
	nu = interpreterProxy.fetchIntegerofObject(0, fftOop);
	fftSize = interpreterProxy.fetchIntegerofObject(1, fftOop);
	oop = interpreterProxy.fetchPointerofObject(2, fftOop);
	sinTableSize = SIZEOF(oop);
	sinTable = checkedFloatPtrOf(oop);
	oop = interpreterProxy.fetchPointerofObject(3, fftOop);
	permTableSize = SIZEOF(oop);
	permTable = checkedWordPtrOf(oop);
	oop = interpreterProxy.fetchPointerofObject(4, fftOop);
	realDataSize = SIZEOF(oop);
	realData = checkedFloatPtrOf(oop);
	oop = interpreterProxy.fetchPointerofObject(5, fftOop);
	imagDataSize = SIZEOF(oop);

	/* Check assumptions about sizes */

	imagData = checkedFloatPtrOf(oop);
	interpreterProxy.success((((((SHL(1, nu)) === fftSize) && (((fftSize >> 2) + 1) === sinTableSize)) && (fftSize === realDataSize)) && (fftSize === imagDataSize)) && (realDataSize === imagDataSize));
	return interpreterProxy.failed() === false;
}

function permuteData() {
	var a;
	var b;
	var end;
	var i;
	var tmp;

	i = 0;
	end = permTableSize;
	while (i < end) {
		a = permTable[i] - 1;
		b = permTable[i + 1] - 1;
		if (!((a < realDataSize) && (b < realDataSize))) {
			return interpreterProxy.success(false);
		}
		tmp = realData[a];
		realData[a] = realData[b];
		realData[b] = tmp;
		tmp = imagData[a];
		imagData[a] = imagData[b];
		imagData[b] = tmp;
		i += 2;
	}
}

function primitiveFFTPermuteData() {
	var rcvr;

	rcvr = interpreterProxy.stackObjectValue(0);
	if (!loadFFTFrom(rcvr)) {
		return null;
	}
	permuteData();
	if (interpreterProxy.failed()) {

		/* permuteData went wrong. Do the permutation again -- this will restore the original order */

		permuteData();
	}
}

function primitiveFFTScaleData() {
	var rcvr;

	rcvr = interpreterProxy.stackObjectValue(0);
	if (!loadFFTFrom(rcvr)) {
		return null;
	}
	scaleData();
}

function primitiveFFTTransformData() {
	var forward;
	var rcvr;

	forward = interpreterProxy.booleanValueOf(interpreterProxy.stackValue(0));
	rcvr = interpreterProxy.stackObjectValue(1);
	if (!loadFFTFrom(rcvr)) {
		return null;
	}
	transformData(forward);
	if (!interpreterProxy.failed()) {
		interpreterProxy.pop(1);
	}
}


/*	Scale all elements by 1/n when doing inverse */

function scaleData() {
	var i;
	var realN;

	if (fftSize <= 1) {
		return null;
	}
	realN = (1.0 / fftSize);
	for (i = 0; i <= (fftSize - 1); i++) {
		realData[i] = (realData[i] * realN);
		imagData[i] = (imagData[i] * realN);
	}
}


/*	Note: This is coded so that is can be run from Squeak. */

function setInterpreter(anInterpreter) {
	var ok;

	interpreterProxy = anInterpreter;
	ok = interpreterProxy.majorVersion() == VM_PROXY_MAJOR;
	if (ok === false) {
		return false;
	}
	ok = interpreterProxy.minorVersion() >= VM_PROXY_MINOR;
	return ok;
}

function transformData(forward) {
	permuteData();
	if (interpreterProxy.failed()) {

		/* permuteData went wrong. Do the permutation again -- this will restore the original order */

		permuteData();
		return null;
	}
	transformForward(forward);
	if (!forward) {
		scaleData();
	}
}

function transformForward(forward) {
	var fftScale;
	var fftSize2;
	var fftSize4;
	var i;
	var ii;
	var imagT;
	var imagU;
	var ip;
	var j;
	var lev;
	var lev1;
	var level;
	var realT;
	var realU;
	var theta;

	fftSize2 = fftSize >> 1;
	fftSize4 = fftSize >> 2;
	for (level = 1; level <= nu; level++) {
		lev = SHL(1, level);
		lev1 = lev >> 1;
		fftScale = DIV(fftSize, lev);
		for (j = 1; j <= lev1; j++) {

			/* pi * (j-1) / lev1 mapped onto 0..n/2 */

			theta = (j - 1) * fftScale;
			if (theta < fftSize4) {

				/* Compute U, the complex multiplier for each level */

				realU = sinTable[(sinTableSize - theta) - 1];
				imagU = sinTable[theta];
			} else {
				realU = 0.0 - sinTable[theta - fftSize4];
				imagU = sinTable[fftSize2 - theta];
			}
			if (!forward) {
				imagU = 0.0 - imagU;
			}
			i = j;
			while (i <= fftSize) {
				ip = (i + lev1) - 1;
				ii = i - 1;
				realT = (realData[ip] * realU) - (imagData[ip] * imagU);
				imagT = (realData[ip] * imagU) + (imagData[ip] * realU);
				realData[ip] = (realData[ii] - realT);
				imagData[ip] = (imagData[ii] - imagT);
				realData[ii] = (realData[ii] + realT);
				imagData[ii] = (imagData[ii] + imagT);
				i += lev;
			}
		}
	}
}


function registerPlugin() {
	if (typeof Squeak === "object" && Squeak.registerExternalModule) {
		Squeak.registerExternalModule("FFTPlugin", {
			primitiveFFTTransformData: primitiveFFTTransformData,
			setInterpreter: setInterpreter,
			primitiveFFTPermuteData: primitiveFFTPermuteData,
			primitiveFFTScaleData: primitiveFFTScaleData,
			getModuleName: getModuleName,
		});
	} else self.setTimeout(registerPlugin, 100);
}

registerPlugin();

})(); // Register module/plugin