Hex / Binary

Code:

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byte[] buff = new byte[4];
buff[0] = 0x34;
buff[1] = 0x23;
buff[2] = 0x00;
buff[3] = 0xF2;


FileStream fs = new FileStream("hex.bin", FileMode.Create, FileAccess.ReadWrite);
BinaryWriter bw = new BinaryWriter(fs);
bw.Write(buff);
bw.Close();
Console.WriteLine("Written to file : hex.bin");

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Right. That writes (34 23 00 F2) to a file in binary (specifically NOT text).

I would like to read a hex number (lets just say 342300F2) from a text file and encode that same hex number to a binary file. I cant work out how to process the text into binaray. Any ideas?

Something like this?

csharp Code:

public void ProcessHex()
        {
            string yourHex = "342300F2";
            string binary = string.Empty;
            if (!yourHex.TryBinaryParse(ref binary))
            {
                Console.WriteLine("Invalid hex format");
            }
            else
            {
                Console.WriteLine(binary);
            }
        }

csharp Code:

public static class Extensions
    {
        public static bool TryBinaryParse(this string hexInput, ref string result)
        {
            try
            {
                if (!System.Text.RegularExpressions.Regex.Match(hexInput, 
                                                                "^[A-Fa-f0-9]+$").Success)
                {
                    return false;
                }
 
                hexInput = hexInput.ToUpper();
 
                Dictionary<char, string> lookup = new Dictionary<char, string>(16);
                {
                    lookup.Add('0', "0000");
                    lookup.Add('1', "0001");
                    lookup.Add('2', "0010");
                    lookup.Add('3', "0011");
                    lookup.Add('4', "0100");
                    lookup.Add('5', "0101");
                    lookup.Add('6', "0110");
                    lookup.Add('7', "0111");
                    lookup.Add('8', "1000");
                    lookup.Add('9', "1001");
                    lookup.Add('A', "1010");
                    lookup.Add('B', "1011");
                    lookup.Add('C', "1100");
                    lookup.Add('D', "1101");
                    lookup.Add('E', "1110");
                    lookup.Add('F', "1111");
                }
 
                result = string.Join(string.Empty, 
                                     hexInput.ToCharArray().Select((c) => lookup[c]).ToArray());
 
                return true;
            }
            catch
            { return false; }
        }
 
    }

I thought it might be cool as an extension.

Ok i dont think ive been clear. What im looking for is if i were to open a file in a hex editor, i would see this:

Code:

---

00000: 34 23 00 F2  xx xx xx xx    ..... ...B.

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I want to take text versions of those hex symbols [34, 23, 00, F2] and encode them in hex. If i were encoding in text the file would look like this:

Code:

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00000: 33 34 32 33 30  30 46 32      34230 0F2..

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I hope that clears things up.