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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
import { type BufReader } from "./buf_reader.ts";import { readInt } from "./read_int.ts";
const MAX_SAFE_INTEGER = BigInt(Number.MAX_SAFE_INTEGER);
/** * Read big endian 64bit long from BufReader * @param buf */export async function readLong(buf: BufReader): Promise<number | null> {  const high = await readInt(buf);  if (high === null) return null;  const low = await readInt(buf);  if (low === null) throw new Deno.errors.UnexpectedEof();  const big = (BigInt(high) << 32n) | BigInt(low);  // We probably should provide a similar API that returns BigInt values.  if (big > MAX_SAFE_INTEGER) {    throw new RangeError(      "Long value too big to be represented as a JavaScript number.",    );  }  return Number(big);}