using GostCryptography.Properties;

namespace GostCryptography.Asn1.Ber
{
    public class Asn1CharRange : Asn1CharSet
    {
        private readonly int _lower;
        private readonly int _upper;

        public Asn1CharRange(int lower, int upper)
            : base((upper - lower) + 1)
        {
            _lower = lower;
            _upper = upper;
        }

        public override int MaxValue
        {
            get { return _upper; }
        }

        public override int GetCharAtIndex(int index)
        {
            index += _lower;

            if (index > _upper)
            {
                throw ExceptionUtility.CryptographicException(Resources.Asn1ConsVioException, "Character index", index);
            }

            return index;
        }

        public override int GetCharIndex(int charValue)
        {
            var num = charValue - _lower;

            if (num < 0)
            {
                throw ExceptionUtility.CryptographicException(Resources.Asn1ConsVioException, "Character index", charValue);
            }

            return num;
        }
    }
}