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