lstd/bytes.ts

import {
  decodeBase64,
  decodeHex,
  encodeBase64,
  encodeHex,
} from "jsr:@std/encoding@^1.0.6";

const encoder = new TextEncoder();
const decoder = new TextDecoder();

export type BinaryLike = string | Uint8Array;

export function from_utf8(s: BinaryLike): string {
  return typeof s === "string" ? s : decoder.decode(s);
}

export function to_utf8(s: BinaryLike): Uint8Array {
  return typeof s === "string" ? encoder.encode(s) : s;
}

export function encode_utf8(s: BinaryLike, buf: Uint8Array): number {
  if (typeof s === "string") return encoder.encodeInto(s, buf).written;
  else return buf.set(s), s.length;
}

export function from_hex(s: BinaryLike): Uint8Array {
  return decodeHex(from_utf8(s));
}

export function to_hex(b: BinaryLike): string {
  return encodeHex(to_utf8(b));
}

export function from_base64(s: BinaryLike): Uint8Array {
  return decodeBase64(from_utf8(s));
}

export function to_base64(b: BinaryLike): string {
  return encodeBase64(to_utf8(b));
}

export function read_u8(b: Uint8Array, i = 0) {
  return b[i];
}

export function write_u8(b: Uint8Array, n: number, i = 0) {
  if (n < 0 || 0xff < n) throw new TypeError(`input out of range, expected u8`);
  b[i] = n;
}

export function read_i8(b: Uint8Array, i = 0) {
  const n = b[i];
  return n | ((n & 0x80) * 0x1fffffe);
}

export function write_i8(b: Uint8Array, n: number, i = 0) {
  if (n < -0x80 || 0x7f < n)
    throw new TypeError(`input out of range, expected i8`);
  b[i] = n;
}

export function read_u16_be(b: Uint8Array, i = 0) {
  return (b[i++] << 8) + b[i];
}

export function write_u16_be(b: Uint8Array, n: number, i = 0) {
  if (n < 0 || 0xffff < n)
    throw new TypeError(`input out of range, expected u16`);
  (b[i++] = n >>> 8), (b[i] = n);
}

export function read_i16_be(b: Uint8Array, i = 0) {
  const n = (b[i++] << 8) + b[i];
  return n | ((n & 0x8000) * 0x1fffe);
}

export function write_i16_be(b: Uint8Array, n: number, i = 0) {
  if (n < -0x8000 || 0x7fff < n)
    throw new TypeError(`input out of range, expected i16`);
  (b[i++] = n >>> 8), (b[i] = n);
}

export function read_u32_be(b: Uint8Array, i = 0) {
  return ((b[i++] << 24) + (b[i++] << 16) + (b[i++] << 8) + b[i]) >>> 0;
}

export function write_u32_be(b: Uint8Array, n: number, i = 0) {
  if (n < 0 || 0xffffffff < n)
    throw new TypeError(`input out of range, expected u32`);
  (b[i++] = n >>> 24), (b[i++] = n >>> 16), (b[i++] = n >>> 8), (b[i] = n);
}

export function read_i32_be(b: Uint8Array, i = 0) {
  return (b[i++] << 24) + (b[i++] << 16) + (b[i++] << 8) + b[i];
}

export function write_i32_be(b: Uint8Array, n: number, i = 0) {
  if (n < -0x80000000 || 0x7fffffff < n)
    throw new TypeError(`input out of range, expected i32`);
  (b[i++] = n >>> 24), (b[i++] = n >>> 16), (b[i++] = n >>> 8), (b[i] = n);
}

export { equals as buf_eq, concat as buf_concat } from "jsr:@std/bytes@^1.0.4";

export function buf_concat_fast(a: Uint8Array, b: Uint8Array) {
  const m = a.length;
  const c = new Uint8Array(m + b.length);
  return c.set(a, 0), c.set(b, m), c;
}

export function buf_resize(buf: Uint8Array, n: number) {
  const res = new Uint8Array(n);
  return res.set(buf.subarray(0, n)), res;
}

export function buf_xor(a: Uint8Array, b: Uint8Array) {
  const n = Math.max(a.length, b.length);
  const c = new Uint8Array(n);
  for (let i = 0; i < n; i++) c[i] = a[i] ^ b[i];
  return c;
}