didier amyot
0d627c9051
The class was already implemented in "https://deno.land/std@0.144.0/streams/conversion.ts". So, I litterally lost 1 day of work! I hate myself.
26 lines
817 B
TypeScript
26 lines
817 B
TypeScript
// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
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import { type BufReader } from "./buf_reader.ts";
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import { readInt } from "./read_int.ts";
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const MAX_SAFE_INTEGER = BigInt(Number.MAX_SAFE_INTEGER);
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/**
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* Read big endian 64bit long from BufReader
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* @param buf
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*/
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export async function readLong(buf: BufReader): Promise<number | null> {
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const high = await readInt(buf);
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if (high === null) return null;
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const low = await readInt(buf);
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if (low === null) throw new Deno.errors.UnexpectedEof();
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const big = (BigInt(high) << 32n) | BigInt(low);
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// We probably should provide a similar API that returns BigInt values.
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if (big > MAX_SAFE_INTEGER) {
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throw new RangeError(
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"Long value too big to be represented as a JavaScript number.",
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);
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}
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return Number(big);
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}
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