mirror of
https://github.com/denoland/deno.git
synced 2024-12-25 08:39:09 -05:00
111 lines
3.1 KiB
TypeScript
111 lines
3.1 KiB
TypeScript
// 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 2018-2020 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));
|
|
}
|