| 1 | |
| 2 | |
| 3 | |
| 4 |
|
| 5 |
|
| 6 | "use strict";
|
| 7 |
|
| 8 |
|
| 9 |
|
| 10 |
|
| 11 | const compileSearch = (funcName, predicate, reversed, extraArgs, earlyOut) => {
|
| 12 | const code = [
|
| 13 | "function ",
|
| 14 | funcName,
|
| 15 | "(a,l,h,",
|
| 16 | extraArgs.join(","),
|
| 17 | "){",
|
| 18 | earlyOut ? "" : "var i=",
|
| 19 | reversed ? "l-1" : "h+1",
|
| 20 | ";while(l<=h){var m=(l+h)>>>1,x=a[m]"
|
| 21 | ];
|
| 22 |
|
| 23 | if (earlyOut) {
|
| 24 | if (predicate.indexOf("c") < 0) {
|
| 25 | code.push(";if(x===y){return m}else if(x<=y){");
|
| 26 | } else {
|
| 27 | code.push(";var p=c(x,y);if(p===0){return m}else if(p<=0){");
|
| 28 | }
|
| 29 | } else {
|
| 30 | code.push(";if(", predicate, "){i=m;");
|
| 31 | }
|
| 32 | if (reversed) {
|
| 33 | code.push("l=m+1}else{h=m-1}");
|
| 34 | } else {
|
| 35 | code.push("h=m-1}else{l=m+1}");
|
| 36 | }
|
| 37 | code.push("}");
|
| 38 | if (earlyOut) {
|
| 39 | code.push("return -1};");
|
| 40 | } else {
|
| 41 | code.push("return i};");
|
| 42 | }
|
| 43 | return code.join("");
|
| 44 | };
|
| 45 |
|
| 46 | const compileBoundsSearch = (predicate, reversed, suffix, earlyOut) => {
|
| 47 | const arg1 = compileSearch(
|
| 48 | "A",
|
| 49 | "x" + predicate + "y",
|
| 50 | reversed,
|
| 51 | ["y"],
|
| 52 | earlyOut
|
| 53 | );
|
| 54 |
|
| 55 | const arg2 = compileSearch(
|
| 56 | "P",
|
| 57 | "c(x,y)" + predicate + "0",
|
| 58 | reversed,
|
| 59 | ["y", "c"],
|
| 60 | earlyOut
|
| 61 | );
|
| 62 |
|
| 63 | const fnHeader = "function dispatchBinarySearch";
|
| 64 |
|
| 65 | const fnBody =
|
| 66 | "(a,y,c,l,h){\
|
| 67 | if(typeof(c)==='function'){\
|
| 68 | return P(a,(l===void 0)?0:l|0,(h===void 0)?a.length-1:h|0,y,c)\
|
| 69 | }else{\
|
| 70 | return A(a,(c===void 0)?0:c|0,(l===void 0)?a.length-1:l|0,y)\
|
| 71 | }}\
|
| 72 | return dispatchBinarySearch";
|
| 73 |
|
| 74 | const fnArgList = [arg1, arg2, fnHeader, suffix, fnBody, suffix];
|
| 75 | const fnSource = fnArgList.join("");
|
| 76 | const result = new Function(fnSource);
|
| 77 | return result();
|
| 78 | };
|
| 79 |
|
| 80 | module.exports = {
|
| 81 | ge: compileBoundsSearch(">=", false, "GE"),
|
| 82 | gt: compileBoundsSearch(">", false, "GT"),
|
| 83 | lt: compileBoundsSearch("<", true, "LT"),
|
| 84 | le: compileBoundsSearch("<=", true, "LE"),
|
| 85 | eq: compileBoundsSearch("-", true, "EQ", true)
|
| 86 | };
|