Function byteAt

source code/utils/bash/bashParser.ts:168–196

(L: Lexer, charIdx: number)

}

function byteAt(L: Lexer, charIdx: number): number {
  // Fast path: ASCII-only prefix means char idx == byte idx
  if (L.byteTable) return L.byteTable[charIdx]!
  // Build table on first non-trivial lookup
  const t = new Uint32Array(L.len + 1)
  let b = 0
  let i = 0
  while (i < L.len) {
    t[i] = b
    const c = L.src.charCodeAt(i)
    if (c < 0x80) {
      b++
      i++
    } else if (c < 0x800) {
      b += 2
      i++
    } else if (c >= 0xd800 && c <= 0xdbff) {
      t[i + 1] = b + 2
      b += 4
      i += 2
    } else {
      b += 3
      i++
    }
  }
  t[L.len] = b
  L.byteTable = t
  return t[charIdx]!
}

function isWordChar(c: string): boolean {
  // Bash word chars: alphanumeric + various punctuation that doesn't start operators