fromBytes static method

BigInt fromBytes(List<int> bytes, { Endian byteOrder = Endian.big, bool sign = false, })

Converts a list of bytes to a BigInt, considering the specified byte order.

The fromBytes method takes a list of bytes and an optional byteOrder parameter (defaulting to big endian). It interprets the byte sequence as a non-negative integer, considering the byte order, and returns the corresponding BigInt representation.

If the byte order is set to little endian, the input bytes are reversed before conversion.

Example Usage:

List<int> bytes = [0x01, 0x02, 0x03, 0x04];
BigInt result = BigIntUtils.fromBytes(bytes); // Result: 16909060

Parameters:

• bytes: The list of bytes to be converted to a BigInt.
• byteOrder: The byte order to interpret the byte sequence (default is big endian). Returns: The BigInt representation of the input byte sequence.

Implementation

static BigInt fromBytes(List<int> bytes,
    {Endian byteOrder = Endian.big, bool sign = false}) {
  if (byteOrder == Endian.little) {
    bytes = List<int>.from(bytes.reversed.toList());
  }
  BigInt result = BigInt.zero;
  for (int i = 0; i < bytes.length; i++) {
    /// Add each byte to the result, considering its position and byte order.
    result += BigInt.from(bytes[bytes.length - i - 1]) << (8 * i);
  }
  if (result == BigInt.zero) return BigInt.zero;
  if (sign && (bytes[0] & 0x80) != 0) {
    final bitLength = bitlengthInBytes(result) * 8;
    return result.toSigned(bitLength);
  }

  return result;
}