System.Net.Http.Headers.ContentRangeHeaderValue.TryCreateContentRange C# (CSharp) Метод

        private static bool TryCreateContentRange(string input, string unit, int fromStartIndex, int fromLength,
            int toStartIndex, int toLength, int lengthStartIndex, int lengthLength, out object parsedValue)
        {
            parsedValue = null;

            long from = 0;
            if ((fromLength > 0) && !HeaderUtilities.TryParseInt64(input.Substring(fromStartIndex, fromLength), out from))
            {
                return false;
            }

            long to = 0;
            if ((toLength > 0) && !HeaderUtilities.TryParseInt64(input.Substring(toStartIndex, toLength), out to))
            {
                return false;
            }

            // 'from' must not be greater than 'to'
            if ((fromLength > 0) && (toLength > 0) && (from > to))
            {
                return false;
            }

            long length = 0;
            if ((lengthLength > 0) && !HeaderUtilities.TryParseInt64(input.Substring(lengthStartIndex, lengthLength),
                out length))
            {
                return false;
            }

            // 'from' and 'to' must be less than 'length'
            if ((toLength > 0) && (lengthLength > 0) && (to >= length))
            {
                return false;
            }

            ContentRangeHeaderValue result = new ContentRangeHeaderValue();
            result._unit = unit;

            if (fromLength > 0)
            {
                result._from = from;
                result._to = to;
            }

            if (lengthLength > 0)
            {
                result._length = length;
            }

            parsedValue = result;
            return true;
        }