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/**
* @license Apache-2.0
*
* Copyright (c) 2026 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 isnanf = require( '@stdlib/math/base/assert/is-nanf' );
var isIntegerf = require( '@stdlib/math/base/assert/is-integerf' );
var gamma = require( '@stdlib/math/base/special/gamma' );
var PINF = require( '@stdlib/constants/float32/pinf' );
var FLOAT32_MAX_NTH_FACTORIAL = require( '@stdlib/constants/float32/max-nth-factorial' );
var float64ToFloat32 = require( '@stdlib/number/float64/base/to-float32' );
var FACTORIALS = require( './factorials.json' );
 
 
// MAIN //
 
/**
* Evaluates the factorial of `x` as a single-precision floating-point number.
*
* @param {number} x - input value
* @returns {number} factorial
*
* @example
* var v = factorialf( 3.0 );
* // returns 6.0
*
* @example
* var v = factorialf( -1.5 );
* // returns ~-3.545
*
* @example
* var v = factorialf( -0.5 );
* // returns ~1.772
*
* @example
* var v = factorialf( 0.5 );
* // returns ~0.886
*
* @example
* var v = factorialf( -10.0 );
* // returns NaN
*
* @example
* var v = factorialf( 34.0 );
* // returns ~2.952e38
*
* @example
* var v = factorialf( 35.0 );
* // returns Infinity
*
* @example
* var v = factorialf( NaN );
* // returns NaN
*/
function factorialf( x ) {
	x = float64ToFloat32( x );
	if ( isnanf( x ) ) {
		return NaN;
	}
	if ( isIntegerf( x ) ) {
		if ( x < 0.0 ) {
			return NaN;
		}
		if ( x <= FLOAT32_MAX_NTH_FACTORIAL ) {
			return float64ToFloat32( FACTORIALS[ x|0 ] );
		}
		return PINF;
	}
	return float64ToFloat32( gamma( x + 1.0 ) );
}
 
 
// EXPORTS //
 
module.exports = factorialf;