text: import crypto from 'crypto'
  
  import { urlAlphabet } from './url-alphabet/index.js'
  
  // It is best to make fewer, larger requests to the crypto module to
  // avoid system call overhead. So, random numbers are generated in a
  // pool. The pool is a Buffer that is larger than the initial random
  // request size by this multiplier. The pool is enlarged if subsequent
  // requests exceed the maximum buffer size.
  const POOL_SIZE_MULTIPLIER = 32
  let pool, poolOffset
  
  let random = bytes => {
    if (!pool || pool.length < bytes) {
      pool = Buffer.allocUnsafe(bytes * POOL_SIZE_MULTIPLIER)
      crypto.randomFillSync(pool)
      poolOffset = 0
    } else if (poolOffset + bytes > pool.length) {
      crypto.randomFillSync(pool)
      poolOffset = 0
    }
  
    let res = pool.subarray(poolOffset, poolOffset + bytes)
    poolOffset += bytes
    return res
  }
  
  let customRandom = (alphabet, size, getRandom) => {
    // First, a bitmask is necessary to generate the ID. The bitmask makes bytes
    // values closer to the alphabet size. The bitmask calculates the closest
    // `2^31 - 1` number, which exceeds the alphabet size.
    // For example, the bitmask for the alphabet size 30 is 31 (00011111).
    let mask = (2 << (31 - Math.clz32((alphabet.length - 1) | 1))) - 1
    // Though, the bitmask solution is not perfect since the bytes exceeding
    // the alphabet size are refused. Therefore, to reliably generate the ID,
    // the random bytes redundancy has to be satisfied.
  
    // Note: every hardware random generator call is performance expensive,
    // because the system call for entropy collection takes a lot of time.
    // So, to avoid additional system calls, extra bytes are requested in advance.
  
    // Next, a step determines how many random bytes to generate.
    // The number of random bytes gets decided upon the ID size, mask,
    // alphabet size, and magic number 1.6 (using 1.6 peaks at performance
    // according to benchmarks).
    let step = Math.ceil((1.6 * mask * size) / alphabet.length)
  
    return () => {
      let id = ''
      while (true) {
        let bytes = getRandom(step)
        // A compact alternative for `for (var i = 0; i < step; i++)`.
        let i = step
        while (i--) {
          // Adding `|| ''` refuses a random byte that exceeds the alphabet size.
          id += alphabet[bytes[i] & mask] || ''
          // `id.length + 1 === size` is a more compact option.
          if (id.length === +size) return id
        }
      }
    }
  }
  
  let customAlphabet = (alphabet, size) => customRandom(alphabet, size, random)
  
  let nanoid = (size = 21) => {
    let bytes = random(size)
    let id = ''
    // A compact alternative for `for (var i = 0; i < step; i++)`.
    while (size--) {
      // It is incorrect to use bytes exceeding the alphabet size.
      // The following mask reduces the random byte in the 0-255 value
      // range to the 0-63 value range. Therefore, adding hacks, such
      // as empty string fallback or magic numbers, is unneccessary because
      // the bitmask trims bytes down to the alphabet size.
      id += urlAlphabet[bytes[size] & 63]
    }
    return id
  }
  
  export { nanoid, customAlphabet, customRandom, urlAlphabet, random }
  