Implement TypedArray#reverse (#532)

std/assembly/index.d.ts

@@ -1139,6 +1139,8 @@ declare abstract class TypedArray<T> implements ArrayBufferView<T> {
   every(callbackfn: (value: T, index: i32, self: this) => bool): bool;
   /** The forEach() method executes a provided function once per array element. This method has the same algorithm as Array.prototype.forEach().*/
   forEach(callbackfn: (value: T, index: i32, self: this) => void): void;
+  /** The reverse() method reverses a typed array in place. The first typed array element becomes the last and the last becomes the first. This method has the same algorithm as Array.prototype.reverse(). */
+  reverse(): this;
 }
 
 /** An array of twos-complement 8-bit signed integers. */

std/assembly/internal/typedarray.ts

@@ -244,3 +244,16 @@ export function FOREACH<TArray extends TypedArray<T>, T>(
     callbackfn(LOAD<T>(buffer, i, byteOffset), i, array);
   }
 }
+
+@inline
+export function REVERSE<TArray extends TypedArray<T>, T>(array: TArray): TArray {
+  var buffer = array.buffer;
+  var byteOffset = array.byteOffset;
+
+  for (let front = 0, back = array.length - 1; front < back; ++front, --back) {
+    let temp = LOAD<T>(buffer, front, byteOffset);
+    STORE<T>(buffer, front, LOAD<T>(buffer, back, byteOffset), byteOffset);
+    STORE<T>(buffer, back, temp, byteOffset);
+  }
+  return array;
+}

std/assembly/typedarray.ts

@@ -10,6 +10,7 @@ import {
   SOME,
   EVERY,
   FOREACH,
+  REVERSE,
 } from "./internal/typedarray";
 
 import {
@@ -68,6 +69,10 @@ export class Int8Array extends TypedArray<i8> {
   forEach(callbackfn: (value: i8, index: i32, self: Int8Array) => void): void {
     FOREACH<Int8Array, i8>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, i8>(this);
+  }
 }
 
 export class Uint8Array extends TypedArray<u8> {
@@ -118,6 +123,10 @@ export class Uint8Array extends TypedArray<u8> {
   forEach(callbackfn: (value: u8, index: i32, self: Uint8Array) => void): void {
     FOREACH<Uint8Array, u8>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, u8>(this);
+  }
 }
 
 export class Uint8ClampedArray extends Uint8Array {
@@ -178,6 +187,10 @@ export class Uint8ClampedArray extends Uint8Array {
   forEach(callbackfn: (value: u8, index: i32, self: Uint8ClampedArray) => void): void {
     FOREACH<Uint8ClampedArray, u8>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, u8>(this);
+  }
 }
 
 export class Int16Array extends TypedArray<i16> {
@@ -228,6 +241,10 @@ export class Int16Array extends TypedArray<i16> {
   forEach(callbackfn: (value: i16, index: i32, self: Int16Array) => void): void {
     FOREACH<Int16Array, i16>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, i16>(this);
+  }
 }
 
 export class Uint16Array extends TypedArray<u16> {
@@ -278,6 +295,10 @@ export class Uint16Array extends TypedArray<u16> {
   forEach(callbackfn: (value: u16, index: i32, self: Uint16Array) => void): void {
     FOREACH<Uint16Array, u16>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, u16>(this);
+  }
 }
 
 export class Int32Array extends TypedArray<i32> {
@@ -328,6 +349,10 @@ export class Int32Array extends TypedArray<i32> {
   forEach(callbackfn: (value: i32, index: i32, self: Int32Array) => void): void {
     FOREACH<Int32Array, i32>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, i32>(this);
+  }
 }
 
 export class Uint32Array extends TypedArray<u32> {
@@ -378,6 +403,10 @@ export class Uint32Array extends TypedArray<u32> {
   forEach(callbackfn: (value: u32, index: i32, self: Uint32Array) => void): void {
     FOREACH<Uint32Array, u32>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, u32>(this);
+  }
 }
 
 export class Int64Array extends TypedArray<i64> {
@@ -428,6 +457,10 @@ export class Int64Array extends TypedArray<i64> {
   forEach(callbackfn: (value: i64, index: i32, self: Int64Array) => void): void {
     FOREACH<Int64Array, i64>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, i64>(this);
+  }
 }
 
 export class Uint64Array extends TypedArray<u64> {
@@ -478,6 +511,10 @@ export class Uint64Array extends TypedArray<u64> {
   forEach(callbackfn: (value: u64, index: i32, self: Uint64Array) => void): void {
     FOREACH<Uint64Array, u64>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, u64>(this);
+  }
 }
 
 export class Float32Array extends TypedArray<f32> {
@@ -528,6 +565,10 @@ export class Float32Array extends TypedArray<f32> {
   forEach(callbackfn: (value: f32, index: i32, self: Float32Array) => void): void {
     FOREACH<Float32Array, f32>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, f32>(this);
+  }
 }
 
 export class Float64Array extends TypedArray<f64> {
@@ -578,4 +619,8 @@ export class Float64Array extends TypedArray<f64> {
   forEach(callbackfn: (value: f64, index: i32, self: Float64Array) => void): void {
     FOREACH<Float64Array, f64>(this, callbackfn);
   }
+
+  reverse(): this {
+    return REVERSE<this, f64>(this);
+  }
 }

tests/compiler/std/typedarray.ts

@@ -362,10 +362,10 @@ function testArrayFindIndex<ArrayType extends TypedArray<T>, T extends number>()
     // testIndex++;
     return value == <T>2;
   });
-  assert(result == 1);
+  assert(result == 1, "result mismatch");
   var failResult = source.findIndex((value: T, index: i32, self: ArrayType): bool => value == <T>4);
 
-  assert(failResult == -1);
+  assert(failResult == -1, "fail result mismatch");
 }
 
 testArrayFindIndex<Int8Array, i8>();
@@ -441,3 +441,42 @@ testArrayForEach<Int64Array, i64>();
 testArrayForEach<Uint64Array, u64>();
 testArrayForEach<Float32Array, f32>();
 testArrayForEach<Float64Array, f64>();
+
+
+var testArrayReverseValues: i32[] = [1, 2, 3, 4, 5, 6, 7, 8, 9];
+function testArrayReverse<TArray extends TypedArray<T>, T extends number>(): void {
+  var values = testArrayReverseValues;
+  var array = instantiate<TArray>(9);
+  var arrayWithOffset = instantiate<TArray>(9);
+  var i: i32 = 0;
+
+  for (i = 0; i < 9; i++) {
+    array[i] = <T>values[i];
+    arrayWithOffset[i] = <T>values[i];
+  }
+
+  array.reverse();
+
+  for (i = 0; i < 9; i++) {
+    assert(array[i] == <T>values[8 - i], "TypedArray reverse value mismatch");
+  }
+
+  var reversedSlice = arrayWithOffset.subarray(4, 8).reverse();
+
+  assert(reversedSlice[0] == <T>8, "TypedArray reverse with byteOffset mismatch");
+  assert(reversedSlice[1] == <T>7, "TypedArray reverse with byteOffset mismatch");
+  assert(reversedSlice[2] == <T>6, "TypedArray reverse with byteOffset mismatch");
+  assert(reversedSlice[3] == <T>5, "TypedArray reverse with byteOffset mismatch");
+}
+
+testArrayReverse<Int8Array, i8>();
+testArrayReverse<Uint8Array, u8>();
+testArrayReverse<Uint8ClampedArray, u8>();
+testArrayReverse<Int16Array, i16>();
+testArrayReverse<Uint16Array, u16>();
+testArrayReverse<Int32Array, i32>();
+testArrayReverse<Uint32Array, u32>();
+testArrayReverse<Int64Array, i64>();
+testArrayReverse<Uint64Array, u64>();
+testArrayReverse<Float32Array, f32>();
+testArrayReverse<Float64Array, f64>();