using System;
using System.Text;
using XYLEM.Communication;

namespace XYLEM.Communication.ValueEncoders
{
    public static class StringEncoderUnicode
    {
        /// <summary>
        /// Standard Windows 1252-encoding page.
        /// </summary>
        static Encoding s_Unicode = Encoding.BigEndianUnicode;

        public static byte[] Encode(string value, int lenght)
        {
            if (value.Length > lenght)
            {
                throw new ArgumentException("value.Length is too long", "value");
            }

            var result = new byte[lenght];
            s_Unicode.GetBytes(value).CopyTo(result, 0);
            return result;
        }

        public static string Decode(byte[] value, int lenght)
        {
            if (value.Length > lenght)
            {
                throw new ArgumentException("value.Length wrong lenght", "value");
            }

            var result = s_Unicode.GetString(value);
            var index = result.IndexOf('\0');
            if (index >= 0)
                return result.Substring(0, result.IndexOf('\0'));
            else
                return result;
        }
    }
}