Asmichi.Utilities.EnvironmentVariableUtil.ValidateNameAndValue C# (CSharp) Method

        public static void ValidateNameAndValue(string name, string value)
        {
            if (name == null)
            {
                throw new ArgumentNullException(nameof(name));
            }
            if (name.Length == 0)
            {
                throw new ArgumentException("Environment variable name must not be empty.", nameof(name));
            }
            if (name.Contains('\0', StringComparison.Ordinal))
            {
                throw new ArgumentException("Environment variable name must not contain '\0'.", nameof(name));
            }
            if (name.Contains('=', StringComparison.Ordinal))
            {
                throw new ArgumentException("Environment variable name must not contain '='.", nameof(name));
            }

            if (!string.IsNullOrEmpty(value))
            {
                if (value.Contains('\0', StringComparison.Ordinal))
                {
                    throw new ArgumentException("Environment variable value must not contain '\0'.", nameof(value));
                }
            }
            else
            {
                // null or empty indicates that this variable should be removed.
            }
        }
    }

        /// <summary>
        /// If <paramref name="value"/> is <see langword="null"/> or empty, removes the entry with <paramref name="name"/> (if any).
        /// Otherwise, removes existing entries with <paramref name="name"/> and inserts an new entry.
        /// </summary>
        // Insertion sort should be sufficient. Generally we do not have tens of extra environment variables.
        public void InsertOrRemove(string name, string value)
        {
            EnvironmentVariableUtil.ValidateNameAndValue(name, value);

            var(start, end) = SearchMatchingElements(_array.AsSpan(0, _count), name);

            Debug.Assert(end >= start);

            if (string.IsNullOrEmpty(value))
            {
                // Remove
                if (start == end)
                {
                    // _array does not have any element with the name. Do nothing.
                }
                else
                {
                    // Remove the matching elements.
                    Array.Copy(_array, end, _array, start, _count - end);
                    _count -= end - start;
                }
            }
            else
            {
                // Insert
                if (start == end)
                {
                    // _array does not have any element with the name. Insert the new element.
                    Array.Copy(_array, end, _array, end + 1, _count - end);
                    _array[start] = new(name, value);
                    _count++;
                }
                else if (end == start + 1)
                {
                    // _array has exactly one element with the name. Just overwrite it.
                    _array[start] = new(name, value);
                }
                else
                {
                    // _array has multiple elements with the name. Overwrite the first one and remove the rest.
                    _array[start] = new(name, value);
                    Array.Copy(_array, end, _array, start + 1, _count - end);
                    _count -= end - start - 1;
                }
            }
        }