typeoscript/std/assembly/arraybuffer.ts at master · typEOScript/typeoscript · GitHub

37 lines (31 loc) · 1.07 KB

import {

HEADER_SIZE,

MAX_BLENGTH,

allocateUnsafe

} from "./internal/arraybuffer";

@sealed

export class ArrayBuffer {

readonly byteLength: i32; // capped to [0, MAX_LENGTH]

// @unsafe

get data(): usize { return changetype<usize>(this) + HEADER_SIZE; }

constructor(length: i32, unsafe: bool = false) {

if (<u32>length > <u32>MAX_BLENGTH) throw new RangeError("Invalid array buffer length");

var buffer = allocateUnsafe(length);

if (!unsafe) memory.fill(changetype<usize>(buffer) + HEADER_SIZE, 0, <usize>length);

return buffer;

}

slice(begin: i32 = 0, end: i32 = MAX_BLENGTH): ArrayBuffer {

var len = this.byteLength;

if (begin < 0) begin = max(len + begin, 0);

else begin = min(begin, len);

if (end < 0) end = max(len + end, 0);

else end = min(end, len);

var newLen = max(end - begin, 0);

var buffer = allocateUnsafe(newLen);

memory.copy(changetype<usize>(buffer) + HEADER_SIZE, changetype<usize>(this) + HEADER_SIZE + begin, newLen);

return buffer;

}

toString(): string {

return "[object ArrayBuffer]";

}

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