using GostCryptography.Properties;

namespace GostCryptography.Asn1.Ber
{
    public static class Asn1RunTime
    {
        public const int LicBer = 1;
        public const int LicPer = 2;
        public const int LicXer = 4;
        public const long Bit0Mask = -9223372036854775808L;

        public static long DecodeIntValue(Asn1DecodeBuffer buffer, int length, bool signExtend)
        {
            var num = 0L;

            if (length > 8)
            {
                throw ExceptionUtility.CryptographicException(Resources.Asn1IntegerValueIsTooLarge);
            }

            for (var i = 0; i < length; i++)
            {
                var num2 = buffer.ReadByte();

                if (num2 < 0)
                {
                    throw ExceptionUtility.CryptographicException(Resources.Asn1EndOfBufferException, buffer.ByteCount);
                }

                if ((i == 0) && signExtend)
                {
                    num = (num2 > 0x7f) ? -1 : 0;
                }

                num = (num * 0x100L) + num2;
            }

            return num;
        }

        public static int GetIdentBytesCount(long ident)
        {
            if (ident < 0x80L)
            {
                return 1;
            }

            if (ident < 0x4000L)
            {
                return 2;
            }

            if (ident < 0x200000L)
            {
                return 3;
            }

            if (ident < 0x10000000L)
            {
                return 4;
            }

            if (ident < 0x800000000L)
            {
                return 5;
            }

            if (ident < 0x40000000000L)
            {
                return 6;
            }

            if (ident < 0x2000000000000L)
            {
                return 7;
            }

            if (ident < 0x100000000000000L)
            {
                return 8;
            }

            return 9;
        }

        public static int GetLongBitCount(long ivalue)
        {
            var num = ivalue & Bit0Mask;
            var num2 = 0;

            if (ivalue != 0L)
            {
                while ((ivalue & Bit0Mask) == num)
                {
                    num2++;
                    ivalue = ivalue << 1;
                }

                if (num == Bit0Mask)
                {
                    num2--;
                }

                return (0x40 - num2);
            }

            return 0;
        }

        public static int GetLongBytesCount(long value)
        {
            var num = 0x7f80000000000000L;
            var num2 = 8;

            if (value < 0L)
            {
                value ^= -1L;
            }

            while ((num2 > 1) && ((value & num) == 0L))
            {
                num = num >> 8;
                num2--;
            }

            return num2;
        }

        public static int GetUlongBytesCount(long value)
        {
            var number = -72057594037927936L;
            var num2 = 8;

            while ((num2 > 1) && ((value & number) == 0L))
            {
                number = Asn1Util.UrShift(number, 8);
                num2--;
            }

            return num2;
        }

        public static int IntTrailingZerosCnt(int w)
        {
            return (0x20 -
                    (((w & 0xffff) != 0)
                        ? (((w & 0xff) != 0) ? ((((w & 15) != 0) ? (((w & 3) != 0) ? (((w & 1) != 0) ? 8 : 7) : (((w & 4) != 0) ? 6 : 5)) : (((w & 0x30) != 0) ? (((w & 0x10) != 0) ? 4 : 3) : (((w & 0x40) != 0) ? 2 : (((w & 0x80) != 0) ? 1 : 0)))) + 0x18) : (((((w = Asn1Util.UrShift(w, 8)) & 15) != 0) ? (((w & 3) != 0) ? (((w & 1) != 0) ? 8 : 7) : (((w & 4) != 0) ? 6 : 5)) : (((w & 0x30) != 0) ? (((w & 0x10) != 0) ? 4 : 3) : (((w & 0x40) != 0) ? 2 : (((w & 0x80) != 0) ? 1 : 0)))) + 0x10))
                        : ((((w = Asn1Util.UrShift(w, 0x10)) & 0xff) != 0) ? ((((w & 15) != 0) ? (((w & 3) != 0) ? (((w & 1) != 0) ? 8 : 7) : (((w & 4) != 0) ? 6 : 5)) : (((w & 0x30) != 0) ? (((w & 0x10) != 0) ? 4 : 3) : (((w & 0x40) != 0) ? 2 : (((w & 0x80) != 0) ? 1 : 0)))) + 8) : ((((w = Asn1Util.UrShift(w, 8)) & 15) != 0) ? (((w & 3) != 0) ? (((w & 1) != 0) ? 8 : 7) : (((w & 4) != 0) ? 6 : 5)) : (((w & 0x30) != 0) ? (((w & 0x10) != 0) ? 4 : 3) : (((w & 0x40) != 0) ? 2 : (((w & 0x80) != 0) ? 1 : 0)))))));
        }
    }
}