CODEWITHSUNDEEP
c#arraysstringcharbyte
strike_noir
strike_noir

Reputation: 4174

Converting string to byte[] creates zero character

In this convert function

public static byte[] GetBytes(string str)
{
    byte[] bytes = new byte[str.Length * sizeof(char)];
    System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
    return bytes;
}

byte[] test = GetBytes("abc");

The resulting array contains zero character

test = [97, 0, 98, 0, 99, 0]

And when we convert byte[] back to string, the result is

string test = "a b c "

How do we make it so it doesn't create those zeroes

Upvotes: 10

Views: 13017

Answers (5)

Evalds Urtans
Evalds Urtans

Reputation: 6704

In reality .net (at least for 4.0) automatically changes size of char when serialized with BinaryWriter

UTF-8 chars have variable length (might not be 1 byte), ASCII chars have 1 byte

'ē' = 2 bytes

'e' = 1 byte

It must be kept in mind when using 

BinaryReader.ReadChars(stream)

In case of word "ēvalds" = 7 bytes size will be different than "evalds" = 6 bytes

Upvotes: 1

Soner Gönül
Soner Gönül

Reputation: 98858

First let's look at what your code does wrong. char is 16-bit (2 byte) in .NET framework. Which means when you write sizeof(char), it returns 2. str.Length is 1, so actually your code will be byte[] bytes = new byte[2] is the same byte[2]. So when you use Buffer.BlockCopy() method, you actually copy 2 bytes from a source array to a destination array. Which means your GetBytes() method returns bytes[0] = 32 and bytes[1] = 0 if your string is " ".

Try to use Encoding.ASCII.GetBytes() instead.

When overridden in a derived class, encodes all the characters in the specified string into a sequence of bytes.

const string input = "Soner Gonul";

byte[] array = Encoding.ASCII.GetBytes(input);

foreach ( byte element in array )
{
     Console.WriteLine("{0} = {1}", element, (char)element);
}

Output:

83 = S
111 = o
110 = n
101 = e
114 = r
32 =
71 = G
111 = o
110 = n
117 = u
108 = l

Upvotes: 6

Ilya Ivanov
Ilya Ivanov

Reputation: 23646

Try to specify Encoding explicitly. You can use next code to convert string to bytes with specified encoding

byte[] bytes = System.Text.Encoding.ASCII.GetBytes("abc");

if you print contents of bytes, you will get { 97, 98, 99 } which doesn't contain zeros, as in your example In your example default encoding using 16 bits per symbol. It can be observer by printing the results of 

System.Text.Encoding.Unicode.GetBytes("abc"); // { 97, 0, 98, 0, 99, 0 }

Then while converting it back, you should select the appropriate encoding:

string str = System.Text.Encoding.ASCII.GetString(bytes);
Console.WriteLine (str);

Prints "abc" as you might expected

Upvotes: 0

prthrokz
prthrokz

Reputation: 1150

Just to clear the confusion about your answer, char type in C# takes 2 bytes. So, string.toCharArray() returns an array in which each item takes 2 bytes of storage. While copying to byte array where each item takes 1 byte storage, there occurs a data loss. Hence the zeroes showing up in result.
As suggested, Encoding.ASCII.GetBytes is a safer option to use.

Upvotes: 1

Abhijeet Nagre
Abhijeet Nagre

Reputation: 926

(97,0) is Unicode representation of 'a'. Unicode represents each character in two bytes. So you can not remove zeros. But you can change Encoding to ASCII. Try following for Converting string to byte[].

byte[] array = Encoding.ASCII.GetBytes(input);

Upvotes: 0

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