@thi.ng/hex/index.js

Hex string formatters for 4/8/16/24/32/48/64bit words, hexdump formatting of binary data

const P32 = 4294967296;
const HEX = "0123456789abcdef";
const U4 = (x) => HEX[x & 15];
const U8 = (x) => HEX[x >>> 4 & 15] + HEX[x & 15];
const U8A = (x, i) => U8(x[i]);
const U16 = (x) => U8(x >>> 8) + U8(x & 255);
const U16BE = (x, i) => U8(x[i]) + U8(x[i + 1]);
const U16LE = (x, i) => U8(x[i + 1]) + U8(x[i]);
const U24 = (x) => U8(x >>> 16) + U16(x);
const U24BE = (x, i) => U8(x[i]) + U16BE(x, i + 1);
const U24LE = (x, i) => U8(x[i + 2]) + U16LE(x, i);
const U32 = (x) => U16(x >>> 16) + U16(x);
const U32BE = (x, i) => U16BE(x, i) + U16BE(x, i + 2);
const U32LE = (x, i) => U16LE(x, i + 2) + U16LE(x, i);
const U48 = (x) => U48HL(x / P32, x % P32);
const U48HL = (hi, lo) => U16(hi) + U32(lo);
const U48BE = (x, i) => U16BE(x, i) + U32BE(x, i + 2);
const U48LE = (x, i) => U16LE(x, i + 4) + U32LE(x, i);
const U64 = (x) => U64HL(x / P32, x % P32);
const U64BIG = (x) => U64HL(Number(x >> BigInt(32)), Number(x & BigInt(P32 - 1)));
const U64HL = (hi, lo) => U32(hi) + U32(lo);
const U64BE = (x, i) => U32BE(x, i) + U32BE(x, i + 4);
const U64LE = (x, i) => U32LE(x, i + 4) + U32LE(x, i);
const uuid = (id, i = 0) => (
  // prettier-ignore
  `${U32BE(id, i)}-${U16BE(id, i + 4)}-${U16BE(id, i + 6)}-${U16BE(id, i + 8)}-${U48BE(id, i + 10)}`
);
const hexdump = (bytes, addr, len, width, ascii) => hexdumpLines(bytes, addr, len, width, ascii).join("\n");
const hexdumpLines = (bytes, addr, len, width = 16, ascii = true) => {
  len = Math.min(len, bytes.length - addr);
  let res = [];
  while (len > 0) {
    const row = [...bytes.subarray(addr, addr + Math.min(len, width))];
    const pad = len < width && ascii ? new Array(width - len).fill("  ") : [];
    res.push(
      [
        U32(addr),
        ...row.map(U8),
        ...pad,
        row.map(
          (x) => x >= 32 && x < 128 ? String.fromCharCode(x) : "."
        ).join("")
      ].join(" ")
    );
    addr += width;
    len -= width;
  }
  return res;
};
export {
  HEX,
  U16,
  U16BE,
  U16LE,
  U24,
  U24BE,
  U24LE,
  U32,
  U32BE,
  U32LE,
  U4,
  U48,
  U48BE,
  U48HL,
  U48LE,
  U64,
  U64BE,
  U64BIG,
  U64HL,
  U64LE,
  U8,
  U8A,
  hexdump,
  hexdumpLines,
  uuid
};