Converting integers to bits/bytes
Hello there. I am not a sessoned programmer and actually have very little experiance in c#.
I have undertaken a project and one of the functions of my porject is to turn string numbers, into bits or bit vectors I beleive they are called. Like I said I am not a brilliant programmer and have had much help with this before. I have currently been changing the strings to ints first. But now I realised that bit vectors are more relevant. The code I am using is:
private void button4_Click(object sender,System.EventArgs e)
{
string text =txtBoxBefore.Text;
string expression =@"\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b";
text =Regex.Replace(text, expression, new MatchEvaluator(IpToUInt));
txtBoxAfter.Text=(text);
}
public static string IpToUInt (Match m)
{
string[] temp =m.Value.Split('.');
uint[] octets = new uint[4];
for (int i = 0; i < 4; i++)
{
octets[i] =uint.Parse(temp[i]);
}
return (octets[0] +(octets[1] << 8) + (octets[2] << 16) +(octets[3] << 24)).ToString();
}
public static string IpFromUInt2 (uint ui)
{
uint[] octets = new uint[4];
octets[3] = ui >> 24;
uint remainder = ui -(octets[3] << 24);
octets[2] = remainder >> 16;
remainder -= octets[2] << 16;
octets[1] = remainder >> 8;
remainder -= octets[1] << 8;
octets[0] = remainder;
string[] temp = new string[4];
for (int i = 0; i < 4; i++)
{
temp[i] = octets[i].ToString();
}
return String.Join(".", temp);
}
Any help would be great.
Thanks
And im also guessing that seeing that ive tried to edit this three times now it doesnt allow for spaccing between sentances.
Alan C BalkanyPosted Feb 26, 2008, 4:20 PM
Integers in C# are ALREADY represented in bits, more commonly called the binary representation.
To access individual bits in an integer, i, you can use the AND operator (&) to zero out all bits except the one you're interested in. You need a second integer to act as a mask, that has all zeros except a single one bit in the position you're interested in.
For example, to access the first three (low-order) bits of i:
int i =
int mask = 1; // 1 is the rightmost bit.
int result;
result = i & mask; // Gives the first bit of i.
mask <<= 1; // Shift the single bit in mask to the second position.
result = i & mask; // Gives the second bit of i.
mask <<= 1; // Shift the mask bit to the third position.
result = i & mask;
In each case, result is zero if the corresponding bit is zero, and non-zero if the corresponding bit is 1.