michael@0: // ES5 15.1.2.2 step 1
michael@0: 
michael@0: /*
michael@0:  * Boundary testing for super-large positive numbers between non-exponential
michael@0:  * and in-exponential-form.
michael@0:  *
michael@0:  * NB: While 1e21 is exactly representable as an IEEE754 double-precision
michael@0:  * number, its nearest neighboring representable values are a good distance
michael@0:  * away, 65536 to be precise.
michael@0:  */
michael@0: 
michael@0: // This is the boundary in theory.
michael@0: assertEq(parseInt(1e21), 1);
michael@0: 
michael@0: // This is the boundary in practice.
michael@0: assertEq(parseInt(1e21 - 65537) > 1e20, true);
michael@0: assertEq(parseInt(1e21 - 65536), 1);
michael@0: assertEq(parseInt(1e21 + 65536), 1);
michael@0: 
michael@0: // Check that we understand floating point accuracy near the boundary
michael@0: assertEq(1e21 - 65537 !== 1e21 - 65536, true);
michael@0: assertEq(1e21 - 65536, 1e21);
michael@0: assertEq(1e21 + 65535, 1e21);
michael@0: assertEq(1e21 + 65536, 1e21);
michael@0: 
michael@0: // ES5 leaves exact precision in ToString(bigMagNum) undefined, which
michael@0: // might make this value inconsistent across implementations (maybe,
michael@0: // nobody's done the math here).  Regardless, it's definitely a number
michael@0: // very close to 1, and not a large-magnitude positive number.
michael@0: assertEq(1e21 + 65537 !== 1e21, true);
michael@0: assertEq(parseInt(1e21 + 65537) < 1.001, true);
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Now do the same tests for super-large negative numbers crossing the
michael@0:  * opposite boundary.
michael@0:  */
michael@0: 
michael@0: // This is the boundary in theory.
michael@0: assertEq(parseInt(-1e21), -1);
michael@0: 
michael@0: // This is the boundary in practice.
michael@0: assertEq(parseInt(-1e21 + 65537) < -1e20, true);
michael@0: assertEq(parseInt(-1e21 + 65536), -1);
michael@0: assertEq(parseInt(-1e21 - 65536), -1);
michael@0: 
michael@0: // Check that we understand floating point accuracy near the boundary
michael@0: assertEq(-1e21 + 65537 !== -1e21 + 65536, true);
michael@0: assertEq(-1e21 + 65536, -1e21);
michael@0: assertEq(-1e21 - 65535, -1e21);
michael@0: assertEq(-1e21 - 65536, -1e21);
michael@0: 
michael@0: // ES5 leaves exact precision in ToString(bigMagNum) undefined, which
michael@0: // might make this value inconsistent across implementations (maybe,
michael@0: // nobody's done the math here).  Regardless, it's definitely a number
michael@0: // very close to -1, and not a large-magnitude negative number.
michael@0: assertEq(-1e21 - 65537 !== 1e21, true);
michael@0: assertEq(parseInt(-1e21 - 65537) > -1.001, true);
michael@0: 
michael@0: 
michael@0: /* Check values around the boundary. */
michael@0: arr = [1e0, 5e1, 9e19, 0.1e20, 1.3e20, 1e20, 9e20, 9.99e20, 0.1e21,
michael@0:        1e21, 1.0e21, 2e21, 2e20, 2.1e22, 9e21, 0.1e22, 1e22, 3e46, 3e23, 3e100, 3.4e200, 7e1000,
michael@0:        1e21, 1e21+65537, 1e21+65536, 1e21-65536, 1e21-65537]; 
michael@0: 
michael@0: /* Check across a range of values in case we missed anything. */
michael@0: for (var i = 0; i < 4000; i++) {
michael@0:     arr.push(1e19 + i*1e19);
michael@0: }
michael@0: 
michael@0: for (var i in arr) {
michael@0:     assertEq(parseInt( arr[i]), parseInt(String( arr[i])));
michael@0:     assertEq(parseInt(-arr[i]), parseInt(String(-arr[i])));
michael@0: }
michael@0: 
michael@0: