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// Ported from Go// https://github.com/golang/go/blob/go1.12.5/src/encoding/hex/hex.go// Copyright 2009 The Go Authors. All rights reserved.// Use of this source code is governed by a BSD-style// license that can be found in the LICENSE file.// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
const hexTable = new TextEncoder().encode("0123456789abcdef");
/** * ErrInvalidByte takes an invalid byte and returns an Error. * @param byte */export function errInvalidByte(byte: number): Error {  return new Error(    "encoding/hex: invalid byte: " +      new TextDecoder().decode(new Uint8Array([byte])),  );}
/** ErrLength returns an error about odd string length. */export function errLength(): Error {  return new Error("encoding/hex: odd length hex string");}
// fromHexChar converts a hex character into its value.function fromHexChar(byte: number): number {  // '0' <= byte && byte <= '9'  if (48 <= byte && byte <= 57) return byte - 48;  // 'a' <= byte && byte <= 'f'  if (97 <= byte && byte <= 102) return byte - 97 + 10;  // 'A' <= byte && byte <= 'F'  if (65 <= byte && byte <= 70) return byte - 65 + 10;
  throw errInvalidByte(byte);}
/** * EncodedLen returns the length of an encoding of n source bytes. Specifically, * it returns n * 2. * @param n */export function encodedLen(n: number): number {  return n * 2;}
/** * Encode encodes `src` into `encodedLen(src.length)` bytes. * @param src */export function encode(src: Uint8Array): Uint8Array {  const dst = new Uint8Array(encodedLen(src.length));  for (let i = 0; i < dst.length; i++) {    const v = src[i];    dst[i * 2] = hexTable[v >> 4];    dst[i * 2 + 1] = hexTable[v & 0x0f];  }  return dst;}
/** * EncodeToString returns the hexadecimal encoding of `src`. * @param src */export function encodeToString(src: Uint8Array): string {  return new TextDecoder().decode(encode(src));}
/** * Decode decodes `src` into `decodedLen(src.length)` bytes * If the input is malformed an error will be thrown * the error. * @param src */export function decode(src: Uint8Array): Uint8Array {  const dst = new Uint8Array(decodedLen(src.length));  for (let i = 0; i < dst.length; i++) {    const a = fromHexChar(src[i * 2]);    const b = fromHexChar(src[i * 2 + 1]);    dst[i] = (a << 4) | b;  }
  if (src.length % 2 == 1) {    // Check for invalid char before reporting bad length,    // since the invalid char (if present) is an earlier problem.    fromHexChar(src[dst.length * 2]);    throw errLength();  }
  return dst;}
/** * DecodedLen returns the length of decoding `x` source bytes. * Specifically, it returns `x / 2`. * @param x */export function decodedLen(x: number): number {  return x >>> 1;}
/** * DecodeString returns the bytes represented by the hexadecimal string `s`. * DecodeString expects that src contains only hexadecimal characters and that * src has even length. * If the input is malformed, DecodeString will throw an error. * @param s the `string` to decode to `Uint8Array` */export function decodeString(s: string): Uint8Array {  return decode(new TextEncoder().encode(s));}