fineui/src/core/proto/number.js

if (!Number.prototype.toFixed || (0.00008).toFixed(3) !== "0.000" ||
    (0.9).toFixed(0) === "0" || (1.255).toFixed(2) !== "1.25" ||
    (1000000000000000128).toFixed(0) !== "1000000000000000128") {
    (function () {
        var base, size, data, i;
        base = 1e7;
        size = 6;
        data = [0, 0, 0, 0, 0, 0];
        function multiply (n, c) {
            var i = -1;
            while (++i < size) {
                c += n * data[i];
                data[i] = c % base;
                c = Math.floor(c / base);
            }
        }

        function divide (n) {
            var i = size, c = 0;
            while (--i >= 0) {
                c += data[i];
                data[i] = Math.floor(c / n);
                c = (c % n) * base;
            }
        }

        function toString () {
            var i = size;
            var s = "";
            while (--i >= 0) {
                if (s !== "" || i === 0 || data[i] !== 0) {
                    var t = String(data[i]);
                    if (s === "") {
                        s = t;
                    } else {
                        s += "0000000".slice(0, 7 - t.length) + t;
                    }
                }
            }
            return s;
        }

        function pow (x, n, acc) {
            return (n === 0 ? acc : (n % 2 === 1 ? pow(x, n - 1, acc * x)
                : pow(x * x, n / 2, acc)));
        }

        function log (x) {
            var n = 0;
            while (x >= 4096) {
                n += 12;
                x /= 4096;
            }
            while (x >= 2) {
                n += 1;
                x /= 2;
            }
            return n;
        }

        Number.prototype.toFixed = function (fractionDigits) {
            var f, x, s, m, e, z, j, k;
            f = Number(fractionDigits);
            f = f !== f ? 0 : Math.floor(f);

            if (f < 0 || f > 20) {
                throw new RangeError("Number.toFixed called with invalid number of decimals");
            }

            x = Number(this);

            if (x !== x) {
                return "NaN";
            }

            if (x <= -1e21 || x > 1e21) {
                return String(x);
            }

            s = "";

            if (x < 0) {
                s = "-";
                x = -x;
            }

            m = "0";

            if (x > 1e-21) {
                // 1e-21<x<1e21
                // -70<log2(x)<70
                e = log(x * pow(2, 69, 1)) - 69;
                z = (e < 0 ? x * pow(2, -e, 1) : x / pow(2, e, 1));
                z *= 0x10000000000000;// Math.pow(2,52);
                e = 52 - e;

                // -18<e<122
                // x=z/2^e
                if (e > 0) {
                    multiply(0, z);
                    j = f;

                    while (j >= 7) {
                        multiply(1e7, 0);
                        j -= 7;
                    }

                    multiply(pow(10, j, 1), 0);
                    j = e - 1;

                    while (j >= 23) {
                        divide(1 << 23);
                        j -= 23;
                    }
                    divide(1 << j);
                    multiply(1, 1);
                    divide(2);
                    m = toString();
                } else {
                    multiply(0, z);
                    multiply(1 << (-e), 0);
                    m = toString() + "0.00000000000000000000".slice(2, 2 + f);
                }
            }

            if (f > 0) {
                k = m.length;

                if (k <= f) {
                    m = s + "0.0000000000000000000".slice(0, f - k + 2) + m;
                } else {
                    m = s + m.slice(0, k - f) + "." + m.slice(k - f);
                }
            } else {
                m = s + m;
            }

            return m;
        };

    })();
}


/**
 ** 加法函数，用来得到精确的加法结果
 ** 说明：javascript的加法结果会有误差，在两个浮点数相加的时候会比较明显。这个函数返回较为精确的加法结果。
 ** 调用：accAdd(arg1,arg2)
 ** 返回值：arg1加上arg2的精确结果
 **/
function accAdd (arg1, arg2) {
    var r1, r2, m, c;
    try {
        r1 = arg1.toString().split(".")[1].length;
    } catch (e) {
        r1 = 0;
    }
    try {
        r2 = arg2.toString().split(".")[1].length;
    } catch (e) {
        r2 = 0;
    }
    c = Math.abs(r1 - r2);
    m = Math.pow(10, Math.max(r1, r2));
    if (c > 0) {
        var cm = Math.pow(10, c);
        if (r1 > r2) {
            arg1 = Number(arg1.toString().replace(".", ""));
            arg2 = Number(arg2.toString().replace(".", "")) * cm;
        } else {
            arg1 = Number(arg1.toString().replace(".", "")) * cm;
            arg2 = Number(arg2.toString().replace(".", ""));
        }
    } else {
        arg1 = Number(arg1.toString().replace(".", ""));
        arg2 = Number(arg2.toString().replace(".", ""));
    }
    return (arg1 + arg2) / m;
}

// 给Number类型增加一个add方法，调用起来更加方便。
Number.prototype.add = function (arg) {
    return accAdd(arg, this);
};
/**
 ** 减法函数，用来得到精确的减法结果
 ** 说明：javascript的减法结果会有误差，在两个浮点数相减的时候会比较明显。这个函数返回较为精确的减法结果。
 ** 调用：accSub(arg1,arg2)
 ** 返回值：arg1加上arg2的精确结果
 **/
function accSub (arg1, arg2) {
    var r1, r2, m, n;
    try {
        r1 = arg1.toString().split(".")[1].length;
    } catch (e) {
        r1 = 0;
    }
    try {
        r2 = arg2.toString().split(".")[1].length;
    } catch (e) {
        r2 = 0;
    }
    m = Math.pow(10, Math.max(r1, r2)); // last modify by deeka //动态控制精度长度
    n = (r1 >= r2) ? r1 : r2;
    return ((arg1 * m - arg2 * m) / m).toFixed(n);
}

// 给Number类型增加一个mul方法，调用起来更加方便。
Number.prototype.sub = function (arg) {
    return accSub(this, arg);
};
/**
 ** 乘法函数，用来得到精确的乘法结果
 ** 说明：javascript的乘法结果会有误差，在两个浮点数相乘的时候会比较明显。这个函数返回较为精确的乘法结果。
 ** 调用：accMul(arg1,arg2)
 ** 返回值：arg1乘以 arg2的精确结果
 **/
function accMul (arg1, arg2) {
    var m = 0, s1 = arg1.toString(), s2 = arg2.toString();
    try {
        m += s1.split(".")[1].length;
    } catch (e) {
    }
    try {
        m += s2.split(".")[1].length;
    } catch (e) {
    }
    return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);
}

// 给Number类型增加一个mul方法，调用起来更加方便。
Number.prototype.mul = function (arg) {
    return accMul(arg, this);
};

/**
 * Return digits length of a number
 * @param {*number} num Input number
 */
function digitLength (num) {
    // Get digit length of e
    var eSplit = num.toString().split(/[eE]/);
    var len = (eSplit[0].split(".")[1] || "").length - (+(eSplit[1] || 0));
    return len > 0 ? len : 0;
}
/**
 * 把小数转成整数，支持科学计数法。如果是小数则放大成整数
 * @param {*number} num 输入数
 */
function float2Fixed (num) {
    if (num.toString().indexOf("e") === -1) {
        return Number(num.toString().replace(".", ""));
    }
    var dLen = digitLength(num);
    return dLen > 0 ? num * Math.pow(10, dLen) : num;
}

/**
 * 精确乘法
 */
function times (num1, num2) {
    var others = [];
    for (var _i = 2; _i < arguments.length; _i++) {
        others[_i - 2] = arguments[_i];
    }
    if (others.length > 0) {
        return times.apply(void 0, [times(num1, num2), others[0]].concat(others.slice(1)));
    }
    var num1Changed = float2Fixed(num1);
    var num2Changed = float2Fixed(num2);
    var baseNum = digitLength(num1) + digitLength(num2);
    var leftValue = num1Changed * num2Changed;
    return leftValue / Math.pow(10, baseNum);
}

/**
 * 精确除法
 */
function accDivide (num1, num2) {
    var others = [];
    for (var _i = 2; _i < arguments.length; _i++) {
        others[_i - 2] = arguments[_i];
    }
    if (others.length > 0) {
        return accDivide.apply(void 0, [accDivide(num1, num2), others[0]].concat(others.slice(1)));
    }
    var num1Changed = float2Fixed(num1);
    var num2Changed = float2Fixed(num2);
    return times((num1Changed / num2Changed), Math.pow(10, digitLength(num2) - digitLength(num1)));
}

// 给Number类型增加一个div方法，调用起来更加方便。
Number.prototype.div = function (arg) {
    return accDivide(this, arg);
};