Function textOrByteStringDeterministic

js/sign/src/cbor/deterministic.ts:107–123

(
  input: Uint8Array,
  index: number
)

// Returns length of the text or byte string element in bytes for which its
// deterministicy has been ensured.
function textOrByteStringDeterministic(
  input: Uint8Array,
  index: number
): number {
  // lengthInBytes is the length of the number representing the length of the
  // text/byte string.
  const { lengthInBytes, value } = unsignedIntegerDeterministic(input, index);
  const totalLength = lengthInBytes + Number(value);

  if (totalLength >= input.length - index) {
    throw new Error(
      "Text or byte string's length cannot exceed the number of bytes left on the input array."
    );
  }

  return totalLength;
}

// Returns length of the CBOR array in bytes and checks that each item on it
// follows the deterministic principles.