Function myers32

packages/webpack-cli/src/webpack-cli.ts:287–328

(a: string, b: string, peq: Uint32Array)

let levenshteinPeq: Uint32Array | undefined;

function myers32(a: string, b: string, peq: Uint32Array): number {
  const n = a.length;
  const m = b.length;
  const lst = 1 << (n - 1);
  let pv = -1;
  let mv = 0;
  let sc = n;
  let i = n;

  while (i--) {
    peq[a.charCodeAt(i)] |= 1 << i;
  }

  for (i = 0; i < m; i++) {
    let eq = peq[b.charCodeAt(i)];
    const xv = eq | mv;

    eq |= ((eq & pv) + pv) ^ pv;
    mv |= ~(eq | pv);
    pv &= eq;

    if (mv & lst) {
      sc++;
    }

    if (pv & lst) {
      sc--;
    }

    mv = (mv << 1) | 1;
    pv = (pv << 1) | ~(xv | mv);
    mv &= xv;
  }

  i = n;

  while (i--) {
    peq[a.charCodeAt(i)] = 0;
  }

  return sc;
}

function myersX(longer: string, shorter: string, peq: Uint32Array): number {
  const n = shorter.length;