Misc string related utils for C#, including deterministic hash method.

string_utils.cs

/// <summary>
/// String-related utils.
/// </summary>
public static class StringUtils
{
    /// <summary>
    /// Convert string to bytes[].
    /// </summary>
    /// <param name="str">String to convert.</param>
    /// <returns>String as bytes[].</returns>
    public static byte[] ToBytes(string str)
    {
        return Encoding.UTF8.GetBytes(str);
    }

    /// <summary>
    /// Convert string to bytes[].
    /// </summary>
    /// <param name="bytes">Bytes to convert.</param>
    /// <param name="start">Index to start converting from.</param>
    /// <param name="count">How many bytes to convert.</param>
    /// <returns>String from bytes.</returns>
    public static string ToString(byte[] bytes, int start = 0, int count = 0)
    {
        if (count == 0) { count = bytes.Length - start; }
        return Encoding.UTF8.GetString(bytes, start, count);
    }

    /// <summary>
    /// Convert bytes array to hex string.
    /// </summary>
    /// <param name="bytes">Bytes to convert.</param>
    /// <returns>Value as hex string.</returns>
    public static string ToHexString(byte[] bytes)
    {
        return String.Concat(Array.ConvertAll(bytes, x => x.ToString("X2")));
    }

    /// <summary>
    /// Convert string to a string containing an MD5 hash of the source.
    /// </summary>
    /// <param name="source">Source string to md5.</param>
    /// <returns>Hashed source as string.</returns>
    public static string ToMd5String(string source)
    {
        using (MD5 md5Hash = MD5.Create())
        {
            return ToString(md5Hash.ComputeHash(ToBytes(source)));
        }
    }

    /// <summary>
    /// Convert string to a hex string containing a SHA256 hash of the source.
    /// </summary>
    /// <param name="source">Source string to SHA256.</param>
    /// <returns>Hashed source as hex string.</returns>
    public static string ToSha256Hex(string source)
    {
        using (SHA256 sha256Hash = SHA256.Create())
        {
            return ToHexString(sha256Hash.ComputeHash(ToBytes(source)));
        }
    }

    /// <summary>
    /// Method to get deterministic hash code from string.
    /// </summary>
    public static int GetDeterministicHashCode(this string str)
    {
        unchecked
        {
            int hash1 = (5381 << 16) + 5381;
            int hash2 = hash1;

            for (int i = 0; i < str.Length; i += 2)
            {
                hash1 = ((hash1 << 5) + hash1) ^ str[i];
                if (i == str.Length - 1)
                    break;
                hash2 = ((hash2 << 5) + hash2) ^ str[i + 1];
            }

            return hash1 + (hash2 * 1566083941);
        }
    }
}