webpack/lib/util/binarySearchBounds.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Mikola Lysenko @mikolalysenko
*/

"use strict";

/* cspell:disable-next-line */
// Refactor: Peter Somogyvari @petermetz

const compileSearch = (funcName, predicate, reversed, extraArgs, earlyOut) => {
	const code = [
		"function ",
		funcName,
		"(a,l,h,",
		extraArgs.join(","),
		"){",
		earlyOut ? "" : "var i=",
		reversed ? "l-1" : "h+1",
		";while(l<=h){var m=(l+h)>>>1,x=a[m]"
	];

	if (earlyOut) {
		if (predicate.indexOf("c") < 0) {
			code.push(";if(x===y){return m}else if(x<=y){");
		} else {
			code.push(";var p=c(x,y);if(p===0){return m}else if(p<=0){");
		}
	} else {
		code.push(";if(", predicate, "){i=m;");
	}
	if (reversed) {
		code.push("l=m+1}else{h=m-1}");
	} else {
		code.push("h=m-1}else{l=m+1}");
	}
	code.push("}");
	if (earlyOut) {
		code.push("return -1};");
	} else {
		code.push("return i};");
	}
	return code.join("");
};

const compileBoundsSearch = (predicate, reversed, suffix, earlyOut) => {
	const arg1 = compileSearch(
		"A",
		"x" + predicate + "y",
		reversed,
		["y"],
		earlyOut
	);

	const arg2 = compileSearch(
		"P",
		"c(x,y)" + predicate + "0",
		reversed,
		["y", "c"],
		earlyOut
	);

	const fnHeader = "function dispatchBinarySearch";

	const fnBody =
		"(a,y,c,l,h){\
if(typeof(c)==='function'){\
return P(a,(l===void 0)?0:l|0,(h===void 0)?a.length-1:h|0,y,c)\
}else{\
return A(a,(c===void 0)?0:c|0,(l===void 0)?a.length-1:l|0,y)\
}}\
return dispatchBinarySearch";

	const fnArgList = [arg1, arg2, fnHeader, suffix, fnBody, suffix];
	const fnSource = fnArgList.join("");
	const result = new Function(fnSource);
	return result();
};

module.exports = {
	ge: compileBoundsSearch(">=", false, "GE"),
	gt: compileBoundsSearch(">", false, "GT"),
	lt: compileBoundsSearch("<", true, "LT"),
	le: compileBoundsSearch("<=", true, "LE"),
	eq: compileBoundsSearch("-", true, "EQ", true)
};