using System;
using System.Collections.Generic;
using System.Text;

namespace Neo.ActiveX.FingerprintReader
{
    class ByteFunctions
    {
        /// <summary>
        /// Converts a byte array to a readable string format.
        /// </summary>
        /// <param name="buf">The byte array to be queried.</param>
        /// <returns>The byte array as a hex string.</returns>
        public static string ByteArrayToHexString(byte[] buf)
        {
            if(buf == null || buf.Length <= 0)
            {
                return null;
            }

            const string digits = "0123456789ABCDEF";
            byte ch = 0x00;
            int i = 0;

            StringBuilder sb = new StringBuilder(buf.Length * 2);

            while(i < buf.Length)
            {
                ch = (byte)(buf[i] & 0xF0); // strip off high nibble
                ch = (byte)(ch >> 4);       // shift the bits down
                ch = (byte)(ch & 0x0F);     // must do this if high order bit is on!
                sb.Append(digits[(int)ch]); // convert the nibble to a String Character
                ch = (byte)(buf[i] & 0x0F); // strip off low nibble 
                sb.Append(digits[(int)ch]); // convert the nibble to a String Character
                i++;
            }

            return sb.ToString();
        }

        /// <summary>
        /// Converts the given hex string to a byte array.
        /// </summary>
        /// <param name="s">The string to be converted.</param>
        /// <returns>A byte array.</returns>
        public static byte[] HexStringToByteArray(string s)
        {
            byte[] buffer = new byte[s.Length / 2];
            for(int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = (byte)Int32.Parse(s.Substring(2 * i, 2), System.Globalization.NumberStyles.HexNumber);
            }
            return buffer;
        }



    }
}