113 lines
2.6 KiB
JavaScript
113 lines
2.6 KiB
JavaScript
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'use strict';
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var $export = require('./_export')
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, toInteger = require('./_to-integer')
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, aNumberValue = require('./_a-number-value')
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, repeat = require('./_string-repeat')
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, $toFixed = 1..toFixed
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, floor = Math.floor
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, data = [0, 0, 0, 0, 0, 0]
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, ERROR = 'Number.toFixed: incorrect invocation!'
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, ZERO = '0';
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var multiply = function(n, c){
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var i = -1
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, c2 = c;
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while(++i < 6){
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c2 += n * data[i];
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data[i] = c2 % 1e7;
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c2 = floor(c2 / 1e7);
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}
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};
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var divide = function(n){
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var i = 6
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, c = 0;
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while(--i >= 0){
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c += data[i];
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data[i] = floor(c / n);
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c = (c % n) * 1e7;
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}
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};
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var numToString = function(){
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var i = 6
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, s = '';
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while(--i >= 0){
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if(s !== '' || i === 0 || data[i] !== 0){
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var t = String(data[i]);
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s = s === '' ? t : s + repeat.call(ZERO, 7 - t.length) + t;
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}
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} return s;
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};
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var pow = function(x, n, acc){
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return n === 0 ? acc : n % 2 === 1 ? pow(x, n - 1, acc * x) : pow(x * x, n / 2, acc);
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};
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var log = function(x){
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var n = 0
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, x2 = x;
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while(x2 >= 4096){
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n += 12;
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x2 /= 4096;
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}
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while(x2 >= 2){
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n += 1;
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x2 /= 2;
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} return n;
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};
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$export($export.P + $export.F * (!!$toFixed && (
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0.00008.toFixed(3) !== '0.000' ||
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0.9.toFixed(0) !== '1' ||
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1.255.toFixed(2) !== '1.25' ||
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1000000000000000128..toFixed(0) !== '1000000000000000128'
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) || !require('./_fails')(function(){
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// V8 ~ Android 4.3-
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$toFixed.call({});
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})), 'Number', {
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toFixed: function toFixed(fractionDigits){
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var x = aNumberValue(this, ERROR)
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, f = toInteger(fractionDigits)
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, s = ''
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, m = ZERO
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, e, z, j, k;
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if(f < 0 || f > 20)throw RangeError(ERROR);
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if(x != x)return 'NaN';
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if(x <= -1e21 || x >= 1e21)return String(x);
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if(x < 0){
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s = '-';
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x = -x;
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}
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if(x > 1e-21){
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e = log(x * pow(2, 69, 1)) - 69;
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z = e < 0 ? x * pow(2, -e, 1) : x / pow(2, e, 1);
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z *= 0x10000000000000;
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e = 52 - e;
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if(e > 0){
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multiply(0, z);
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j = f;
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while(j >= 7){
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multiply(1e7, 0);
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j -= 7;
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}
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multiply(pow(10, j, 1), 0);
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j = e - 1;
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while(j >= 23){
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divide(1 << 23);
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j -= 23;
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}
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divide(1 << j);
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multiply(1, 1);
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divide(2);
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m = numToString();
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} else {
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multiply(0, z);
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multiply(1 << -e, 0);
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m = numToString() + repeat.call(ZERO, f);
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}
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}
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if(f > 0){
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k = m.length;
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m = s + (k <= f ? '0.' + repeat.call(ZERO, f - k) + m : m.slice(0, k - f) + '.' + m.slice(k - f));
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} else {
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m = s + m;
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} return m;
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}
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});
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