Method performEncode

src/Encoder/Base32.js:112–158

* Performs encode on given content. * @protected * @param {Chain} content * @return {number[]|string|Uint8Array|Chain|Promise} Encoded content

(content)

   * @return {number[]|string|Uint8Array|Chain|Promise} Encoded content
   */
  performEncode (content) {
    const { alphabet, padding } = this.getVariantOptions()
    const alphabetCodePoints = alphabet.getCodePoints()

    // Prepare input and output arrays
    const input = content.getBytes()
    const inputLength = input.length
    const resultLength = Math.ceil(inputLength / 5) * 8
    const result = new Array(resultLength)
    let j = 0

    let shift = 3
    let carry = 0
    let byte, index

    // Go through every input byte
    for (let i = 0; i < inputLength; i++) {
      byte = input[i]

      index = carry | (byte >> shift)
      result[j++] = alphabetCodePoints[index & 0x1f]

      if (shift > 5) {
        shift -= 5
        index = byte >> shift
        result[j++] = alphabetCodePoints[index & 0x1f]
      }

      shift = 5 - shift
      carry = byte << shift
      shift = 8 - shift
    }

    if (shift !== 3) {
      result[j++] = alphabetCodePoints[carry & 0x1f]
    }

    // Finalize result padding
    if (padding !== null) {
      while (j < resultLength) {
        result[j++] = padding
      }
      return result
    } else {
      return result.slice(0, j)
    }
  }

  /**
   * Performs decode on given content.