using System.Text;

public static class FastConcatUtility
{
    static readonly StringBuilder _stringBuilder = new StringBuilder(256);

    public static string FastConcat<T>(this string str1, T str2)
    {
        lock (_stringBuilder)
        {
            _stringBuilder.Length = 0;

            _stringBuilder.Append(str1);
            _stringBuilder.Append(str2);

            return _stringBuilder.ToString();
        }
    }

    public static string FastConcat(this string str1, string str2, string str3)
    {
        lock (_stringBuilder)
        {
            _stringBuilder.Length = 0;

            _stringBuilder.Append(str1);
            _stringBuilder.Append(str2);
            _stringBuilder.Append(str3);

            return _stringBuilder.ToString();
        }
    }

    public static string FastConcat(this string str1, string str2, string str3, string str4)
    {
        lock (_stringBuilder)
        {
            _stringBuilder.Length = 0;

            _stringBuilder.Append(str1);
            _stringBuilder.Append(str2);
            _stringBuilder.Append(str3);
            _stringBuilder.Append(str4);


            return _stringBuilder.ToString();
        }
    }

    public static string FastConcat(this string str1, string str2, string str3, string str4, string str5)
    {
        lock (_stringBuilder)
        {
            _stringBuilder.Length = 0;

            _stringBuilder.Append(str1);
            _stringBuilder.Append(str2);
            _stringBuilder.Append(str3);
            _stringBuilder.Append(str4);
            _stringBuilder.Append(str5);

            return _stringBuilder.ToString();
        }
    }

    public static string FastJoin(this string[] str)
    {
        lock (_stringBuilder)
        {
            _stringBuilder.Length = 0;

            for (int i = 0; i < str.Length; i++)
                _stringBuilder.Append(str[i]);

            return _stringBuilder.ToString();
        }
    }

    public static string FastJoin(this string[] str, string str1)
    {
        lock (_stringBuilder)
        {
            _stringBuilder.Length = 0;

            for (int i = 0; i < str.Length; i++)
                _stringBuilder.Append(str[i]);

            _stringBuilder.Append(str1);

            return _stringBuilder.ToString();
        }
    }
}

namespace Utility
{
#if UNITY_5 || UNITY_5_3_OR_NEWER
#endif
}