[joaquimandrade]

For those who don't know what i'm talking about (This is all in the pawn manual):

A cell is a contiguous region of memory composed of 4 bytes (32 bits) (normally).

A character can be represented with only 1 byte (8 bits) (And it is in other languages, being also a type definition)

In Pawn there is only the cell type. So, normally, to hold a character, a cell is used. But, Pawn also permits the storage of chars in 1 byte sized memory regions. That permits us to use a cell as a 4 characters holder. (What is called "to pack a string")

To create a variable to be used as a "packed string holder" the syntax is:

PHP Code:

new packedStringHolder[5 char] 


That will create a new variable called packedStringHolder that will have cells enough to hold 5 packed chars. That means that it will have 2 cells. The first cell will hold 4 packed chars, the second one will hold 1 packed char.

To create a packed string the syntax is:

new packedStringHolder[] = !"string"

To access a char in a packed string the syntax is:

packetStringHolder{index}

So, packetStringHolder{0} == 's' .

You will not find many uses for this data storage way since there aren't natives for them (i think) but, for the case that we are talking about here, it fits:

PHP Code:

new bool:isConnected[33 char]

public client_authorized(id)
{
    isConnected{id} = true;
}
public client_disconnect(id)
{
    isConnected{id} = false;
} 


That would probably be as fast as using a 33 cells array but, will use 9 cells instead.

The formula to calculate the cells needed is:

(packed chars / 4) + (packed chars % 4) ? 0 : 1

So, for 33 packed chars:

(33 / 4) + (33 % 4) ? 0 : 1

8 + 1 = 9

[Arkshine]

Thanks for your explanations. Now I understand better what was a packed string.

[joaquimandrade]

Originally Posted by arkshine Thanks for your explanations. Now I understand better what was a packed string.

[Arkshine]

You should make a separate thread for that.

[joaquimandrade]

Originally Posted by arkshine You should make a separate thread for that.

Ok. Tomorrow i will.

[Bugsy]

The Pawn language guide discusses packed\unpacked strings FYI.

[Arkshine]

I know, that's why I said 'was'. How it's explained I have some difficulties to understand it. joaquimandrade explains well and with some examples it should be a good tutorial about it.

[Bugsy]

I absolutely agree, I was just putting it up there for anyone interested in seeing what the guide has to say.

[joaquimandrade]

If someone is interested on knowing how to use bit storage for values bigger than 31:

PHP Code:

save(x)
{
    holder[x / 32] |= 1 << (x % 32);
}

exists(x)
{
    return holder[x / 32] & 1 << (x % 32);
}

remove(x)
{
    holder[x / 32] &= ~(1 << (x % 32))
} 


It's a memory tradeoff.

[Bugsy]

Nice find