Source code
Revision control
Copy as Markdown
Other Tools
// Copies bytes bit-wise if source and target type are the same.
// Only detectable when using floating point typed arrays.
const float32Constructors = anyTypedArrayConstructors.filter(isFloatConstructor)
.filter(c => c.BYTES_PER_ELEMENT === 4);
const float64Constructors = anyTypedArrayConstructors.filter(isFloatConstructor)
.filter(c => c.BYTES_PER_ELEMENT === 8);
// Also test with cross-compartment typed arrays.
const otherGlobal = newGlobal();
float32Constructors.push(otherGlobal.Float32Array);
float64Constructors.push(otherGlobal.Float64Array);
function* p(xs, ys) {
for (let x of xs) {
for (let y of ys) {
yield [x, y];
}
}
}
const isLittleEndian = new Uint8Array(new Uint16Array([1]).buffer)[0] !== 0;
function geti64(i32, i) {
return [i32[2 * i + isLittleEndian], i32[2 * i + !isLittleEndian]];
}
function seti64(i32, i, [hi, lo]) {
i32[i * 2 + isLittleEndian] = hi;
i32[i * 2 + !isLittleEndian] = lo;
}
const NaNs = {
Float32: [
0x7F800001|0, // smallest SNaN
0x7FBFFFFF|0, // largest SNaN
0x7FC00000|0, // smallest QNaN
0x7FFFFFFF|0, // largest QNaN
0xFF800001|0, // smallest SNaN, sign-bit set
0xFFBFFFFF|0, // largest SNaN, sign-bit set
0xFFC00000|0, // smallest QNaN, sign-bit set
0xFFFFFFFF|0, // largest QNaN, sign-bit set
],
Float64: [
[0x7FF00000|0, 0x00000001|0], // smallest SNaN
[0x7FF7FFFF|0, 0xFFFFFFFF|0], // largest SNaN
[0x7FF80000|0, 0x00000000|0], // smallest QNaN
[0x7FFFFFFF|0, 0xFFFFFFFF|0], // largest QNaN
[0xFFF00000|0, 0x00000001|0], // smallest SNaN, sign-bit set
[0xFFF7FFFF|0, 0xFFFFFFFF|0], // largest SNaN, sign-bit set
[0xFFF80000|0, 0x00000000|0], // smallest QNaN, sign-bit set
[0xFFFFFFFF|0, 0xFFFFFFFF|0], // largest QNaN, sign-bit set
],
};
const cNaN = {
Float32: new Int32Array(new Float32Array([NaN]).buffer)[0],
Float64: geti64(new Int32Array(new Float64Array([NaN]).buffer), 0),
};
// Float32 -> Float32
for (let [sourceConstructor, targetConstructor] of p(float32Constructors, float32Constructors)) {
let len = NaNs.Float32.length;
let f32 = new sourceConstructor(len);
let i32 = new Int32Array(f32.buffer);
f32.constructor = targetConstructor;
for (let i = 0; i < len; ++i) {
i32[i] = NaNs.Float32[i];
}
let rf32 = f32.slice(0);
let ri32 = new Int32Array(rf32.buffer);
assertEq(rf32.length, len);
assertEq(ri32.length, len);
// Same bits.
for (let i = 0; i < len; ++i) {
assertEq(ri32[i], NaNs.Float32[i]);
}
}
// Float32 -> Float64
for (let [sourceConstructor, targetConstructor] of p(float32Constructors, float64Constructors)) {
let len = NaNs.Float32.length;
let f32 = new sourceConstructor(len);
let i32 = new Int32Array(f32.buffer);
f32.constructor = targetConstructor;
for (let i = 0; i < len; ++i) {
i32[i] = NaNs.Float32[i];
}
let rf64 = f32.slice(0);
let ri32 = new Int32Array(rf64.buffer);
assertEq(rf64.length, len);
assertEq(ri32.length, 2 * len);
// NaN bits canonicalized.
for (let i = 0; i < len; ++i) {
assertEqArray(geti64(ri32, i), cNaN.Float64);
}
}
// Float64 -> Float64
for (let [sourceConstructor, targetConstructor] of p(float64Constructors, float64Constructors)) {
let len = NaNs.Float64.length;
let f64 = new sourceConstructor(len);
let i32 = new Int32Array(f64.buffer);
f64.constructor = targetConstructor;
for (let i = 0; i < len; ++i) {
seti64(i32, i, NaNs.Float64[i]);
}
let rf64 = f64.slice(0);
let ri32 = new Int32Array(rf64.buffer);
assertEq(rf64.length, len);
assertEq(ri32.length, 2 * len);
// Same bits.
for (let i = 0; i < len; ++i) {
assertEqArray(geti64(ri32, i), NaNs.Float64[i]);
}
}
// Float64 -> Float32
for (let [sourceConstructor, targetConstructor] of p(float64Constructors, float32Constructors)) {
let len = NaNs.Float64.length;
let f64 = new sourceConstructor(len);
let i32 = new Int32Array(f64.buffer);
f64.constructor = targetConstructor;
for (let i = 0; i < len; ++i) {
seti64(i32, i, NaNs.Float64[i]);
}
let rf32 = f64.slice(0);
let ri32 = new Int32Array(rf32.buffer);
assertEq(rf32.length, len);
assertEq(ri32.length, len);
// NaN bits canonicalized.
for (let i = 0; i < len; ++i) {
assertEqArray(ri32[i], cNaN.Float32);
}
}
if (typeof reportCompare === "function")
reportCompare(true, true);