function sliceLength( slice ) {
	var inc;
	var x1;
	var x2;

	x1 = slice.start;
	x2 = slice.stop;
	inc = slice.step;

	// For a normalized slice, stop should only be `null` when the increment is negative...
	if ( x2 === null ) {
		x2 = -1; // set to -1 to ensure that the first element is included
	}
	if (
		// If the increment is positive, the slice is empty whenever the starting index is greater than or equal to the stopping index:
		( inc > 0 && x1 >= x2 ) ||

		// If the increment is negative, the slice is empty whenever the starting index is less than or equal to the stopping index:
		( inc < 0 && x1 <= x2 )
	) {
		return 0;
	}
	return ceil( ( x2 - x1 ) / inc );
}
Returns the number of elements in a normalized slice.

@param {Slice} slice - normalized Slice object
@returns {NonNegativeInteger} number of elements

@example
var Slice = require( '@stdlib/slice/ctor' );
var normalizeSlice = require( '@stdlib/slice/base/normalize-slice' );

var s = new Slice( 2, null, 1 );
// returns <Slice>

var v = sliceLength( normalizeSlice( s, 10, false ) );
// returns 8

v = sliceLength( normalizeSlice( s, 11, false ) );
// returns 9

v = sliceLength( normalizeSlice( s, 5, false ) );
// returns 3

@example
var Slice = require( '@stdlib/slice/ctor' );
var normalizeSlice = require( '@stdlib/slice/base/normalize-slice' );

var s = new Slice( 2, null, 2 );
// returns <Slice>

var v = sliceLength( normalizeSlice( s, 10, false ) );
// returns 4

v = sliceLength( normalizeSlice( s, 11, false ) );
// returns 5

v = sliceLength( normalizeSlice( s, 5, false ) );
// returns 2

@example
var Slice = require( '@stdlib/slice/ctor' );
var normalizeSlice = require( '@stdlib/slice/base/normalize-slice' );

var s = new Slice( -1, null, -2 );

var v = sliceLength( normalizeSlice( s, 10, false ) );
// returns 5

v = sliceLength( normalizeSlice( s, 11, false ) );
// returns 6

v = sliceLength( normalizeSlice( s, 5, false ) );
// returns 3

@example
var Slice = require( '@stdlib/slice/ctor' );
var normalizeSlice = require( '@stdlib/slice/base/normalize-slice' );

var s = new Slice( 3, 5, -1 );

var v = sliceLength( normalizeSlice( s, 10, false ) );
// returns 0

v = sliceLength( normalizeSlice( s, 11, false ) );
// returns 0

v = sliceLength( normalizeSlice( s, 5, false ) );
// returns 0

@example
var Slice = require( '@stdlib/slice/ctor' );
var normalizeSlice = require( '@stdlib/slice/base/normalize-slice' );

var s = new Slice( 5, 3, 1 );

var v = sliceLength( normalizeSlice( s, 10, false ) );
// returns 0

v = sliceLength( normalizeSlice( s, 11, false ) );
// returns 0

v = sliceLength( normalizeSlice( s, 5, false ) );
// returns 0