# MySocketIOTest / myiotestb / static / web-socket-js / flash-src / third-party / com / hurlant / math / BarrettReduction.as

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90``` ```package com.hurlant.math { use namespace bi_internal; internal class BarrettReduction implements IReduction { private var m:BigInteger; private var r2:BigInteger; private var q3:BigInteger; private var mu:BigInteger; public function BarrettReduction(m:BigInteger) { // setup Barrett r2 = new BigInteger; q3 = new BigInteger; BigInteger.ONE.dlShiftTo(2*m.t, r2); mu = r2.divide(m); this.m = m; } public function revert(x:BigInteger):BigInteger { return x; } /** * * @param x * @param y * @param r = x*y mod m; x != r * */ public function mulTo(x:BigInteger, y:BigInteger, r:BigInteger):void { x.multiplyTo(y, r); reduce(r); } /** * * @param x * @param r = x^2 mod m; x != r * */ public function sqrTo(x:BigInteger, r:BigInteger):void { x.squareTo(r); reduce(r); } public function convert(x:BigInteger):BigInteger { if (x.s<0 || x.t>2*m.t) { return x.mod(m); } else if (x.compareTo(m)<0) { return x; } else { var r:BigInteger = new BigInteger; x.copyTo(r); reduce(r); return r; } } /** * * @param x = x mod m (HAC 14.42) * */ public function reduce(lx:BigInteger):void { var x:BigInteger = lx as BigInteger; x.drShiftTo(m.t-1,r2); if (x.t>m.t+1) { x.t = m.t+1; x.clamp(); } mu.multiplyUpperTo(r2, m.t+1, q3); m.multiplyLowerTo(q3, m.t+1, r2); while (x.compareTo(r2)<0) { x.dAddOffset(1, m.t+1); } x.subTo(r2,x); while (x.compareTo(m)>=0) { x.subTo(m,x); } } } } ```