New ArrayBuffer/TypedArray; Stdlib restructure; Fix importing stdlib in stdlib; Traverse constructors; Allow initialization of readonly instance fields in constructors

std/assembly/internal/arraybuffer.ts

@@ -0,0 +1,34 @@
+import { AL_MASK, MAX_SIZE_32 } from "./allocator";
+
+/** Size of an ArrayBuffer header. */
+export const HEADER_SIZE: usize = (offsetof<ArrayBuffer>() + AL_MASK) & ~AL_MASK;
+
+/** Maximum byte length of an ArrayBuffer. */
+export const MAX_BLENGTH: i32 = <i32>MAX_SIZE_32 - HEADER_SIZE;
+
+/** Computes an ArrayBuffer's size in memory. */
+export function computeSize(byteLength: i32): usize {
+  // round up to power of 2, with HEADER_SIZE=8:
+  // 0            -> 2^3  = 8
+  // 1..8         -> 2^4  = 16
+  // 9..24        -> 2^5  = 32
+  // ...
+  // MAX_LENGTH   -> 2^30 = 0x40000000 (MAX_SIZE_32)
+  return <usize>1 << <usize>(<u32>32 - clz<u32>(byteLength + HEADER_SIZE - 1));
+}
+
+/** Allocates a raw ArrayBuffer with uninitialized contents. */
+export function allocate(byteLength: i32): ArrayBuffer {
+  assert(<u32>byteLength <= <u32>MAX_BLENGTH);
+  var buffer = allocate_memory(computeSize(byteLength));
+  store<i32>(buffer, byteLength, offsetof<ArrayBuffer>("byteLength"));
+  return changetype<ArrayBuffer>(buffer);
+}
+
+/** Common typed array interface. Not a global object. */
+// export declare interface ArrayBufferView<T> {
+//   readonly buffer: ArrayBuffer;
+//   readonly byteOffset: i32;
+//   readonly byteLength: i32;
+//   readonly length: i32;
+// }