text: /**
  * @license Apache-2.0
  *
  * Copyright (c) 2018 The Stdlib Authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *    http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
  
  'use strict';
  
  // MODULES //
  
  var isnan = require( '@stdlib/math-base-assert-is-nan' );
  var isInfinite = require( '@stdlib/math-base-assert-is-infinite' );
  var pow = require( '@stdlib/math-base-special-pow' );
  var log10 = require( '@stdlib/math-base-special-log10' );
  var ln = require( '@stdlib/math-base-special-ln' );
  var abs = require( '@stdlib/math-base-special-abs' );
  var floor = require( '@stdlib/math-base-special-floor' );
  var exponent = require( '@stdlib/number-float64-base-exponent' );
  var trunc = require( '@stdlib/math-base-special-trunc' );
  
  
  // MAIN //
  
  /**
  * Rounds a numeric value to the nearest number toward zero with \\(n\\) significant figures.
  *
  * @param {number} x - input value
  * @param {PositiveInteger} n - number of significant figures
  * @param {PositiveInteger} [b=10] - base
  * @returns {number} rounded value
  *
  * @example
  * var v = truncsd( 3.141592653589793, 5 );
  * // returns 3.1415
  *
  * @example
  * var v = truncsd( 3.141592653589793, 1 );
  * // returns 3.0
  *
  * @example
  * var v = truncsd( 12368.0, 2 );
  * // returns 12000.0
  *
  * @example
  * var v = truncsd( 0.0313, 2, 2 );
  * // returns 0.03125
  */
  function truncsd( x, n, b ) {
  	var base;
  	var exp;
  	var s;
  	var y;
  	if (
  		isnan( x ) ||
  		isnan( n ) ||
  		n < 1 ||
  		isInfinite( n )
  	) {
  		return NaN;
  	}
  	if ( arguments.length > 2 ) {
  		if (
  			isnan( b ) ||
  			b <= 0 ||
  			isInfinite( b )
  		) {
  			return NaN;
  		}
  		base = b;
  	} else {
  		base = 10;
  	}
  	if ( isInfinite( x ) || x === 0.0 ) {
  		return x;
  	}
  	if ( base === 10 ) {
  		exp = log10( abs( x ) );
  	}
  	else if ( base === 2 ) {
  		exp = exponent( abs( x ) );
  	}
  	else {
  		exp = ln( abs(x) ) / ln( base );
  	}
  	exp = floor( exp - n + 1.0 );
  	s = pow( base, abs( exp ) );
  
  	// Check for overflow:
  	if ( isInfinite( s ) ) {
  		return x;
  	}
  	// To avoid numerical stability issues due to floating-point rounding error (e.g., 3.55/0.1-35.5 = -7.105427357601e-15 and 3.55*10-35.5 = 0), we must treat positive and negative exponents separately.
  	if ( exp < 0 ) {
  		y = trunc( x * s ) / s;
  	} else {
  		y = trunc( x / s ) * s;
  	}
  	// Check for overflow:
  	if ( isInfinite( y ) ) {
  		return x;
  	}
  	return y;
  }
  
  
  // EXPORTS //
  
  module.exports = truncsd;
  