ceil10.js (2221B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var isnan = require( './../../../../base/assert/is-nan' ); 24 var isInfinite = require( './../../../../base/assert/is-infinite' ); 25 var pow = require( './../../../../base/special/pow' ); 26 var floor = require( './../../../../base/special/floor' ); 27 var ceil = require( './../../../../base/special/ceil' ); 28 var log10 = require( './../../../../base/special/log10' ); 29 var MAX_EXP = require( '@stdlib/constants/float64/max-base10-exponent' ); 30 var MIN_EXP_SUBNORMAL = require( '@stdlib/constants/float64/min-base10-exponent-subnormal' ); 31 var PINF = require( '@stdlib/constants/float64/pinf' ); 32 33 34 // MAIN // 35 36 /** 37 * Rounds a numeric value to the nearest power of `10` toward positive infinity. 38 * 39 * @param {number} x - input value 40 * @returns {number} rounded value 41 * 42 * @example 43 * var v = ceil10( 3.141592653589793 ); 44 * // returns 10.0 45 * 46 * @example 47 * var v = ceil10( 9.0 ); 48 * // returns 10.0 49 * 50 * @example 51 * var v = ceil10( -0.314 ); 52 * // returns -0.1 53 */ 54 function ceil10( x ) { 55 var sign; 56 var p; 57 if ( 58 isnan( x ) || 59 isInfinite( x ) || 60 x === 0.0 61 ) { 62 return x; 63 } 64 if ( x < 0 ) { 65 x = -x; 66 sign = -1.0; 67 } else { 68 sign = 1.0; 69 } 70 // Solve the equation `10^p = x` for `p`: 71 p = log10( x ); 72 73 // Determine a power of 10 which rounds the input value toward positive infinity: 74 if ( sign === -1.0 ) { 75 p = floor( p ); 76 } else { 77 p = ceil( p ); 78 } 79 // Handle underflow: 80 if ( p <= MIN_EXP_SUBNORMAL ) { 81 return sign * 0.0; // sign-preserving 82 } 83 // Handle overflow: 84 if ( p > MAX_EXP ) { 85 return PINF; 86 } 87 return sign * pow( 10.0, p ); 88 } 89 90 91 // EXPORTS // 92 93 module.exports = ceil10;