Convert Hex String to Integer

Squirrel Code
1

I’m trying to split an RGB string in hex, for example: ‘00cc00’, into three integers. Splitting the string into two character chunks is easy. Is there something similar to STRING.tointeger() that will accept hex? Or has anyone written a function to do this that they’re willing to share?

2

There is likely a more elegant way to do this but here is a function I wrote you can adapt - it expects a string in the form “0xaBcD11” so you can either rewrite the function or call it with strNumToInt(“0x” + STRING)

`function strNumToInt(str){
local retVal;

if(str == null) return;

try{
    if(typeof str == "string" && str.len() >= 3 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')){
        retVal = 0;
        local bitShift = 0
        local tempVal;
        for(local i=str.len()-1; i >= 2 ; i--){
            switch(str[i]){
                case 'a':
                case 'A':
                    tempVal = 10;
                    break;
                case 'b':
                case 'B':
                    tempVal = 11;
                    break;
                case 'c':
                case 'C':
                    tempVal = 12;
                    break;
                case 'd':
                case 'D':
                    tempVal = 13;
                    break;
                case 'e':
                case 'E':
                    tempVal = 14;
                    break;
                case 'f':
                case 'F':
                    tempVal = 15;
                    break;
                case '0':
                case '1':
                case '2':
                case '3':
                case '4':
                case '5':
                case '6':
                case '7':
                case '8':
                case '9':
                    tempVal = str[i].tointeger() - 48;
                    break;
                default:
                    server.log("ERROR - INVALID HEX STRING")
                    return;                     
            }
            retVal += tempVal << 4*bitShift++
        }
        return retVal;
    } else {
        return str.tointeger();
    }
} catch(ex){
    retVal = null;
    server.log(ex);
}

}`

3

Thanks, I changed it up a little to not need the ‘0x’.

If anyone knows a more efficient way let me know.

4

http://forums.electricimp.com/discussion/comment/364#Comment_364
I posted code on how to convert the hex color into values for the RGB LED on the Hannah.

Here are two functions that I put into the imp program:

function Hex2RGB(v)
{
local vString = v.tostring().toupper();
local hexChars = “0123456789ABCDEF”;

// Make sure it's 6 digits long
if(vString.len() == 6)
{
    // Return the new colors
    return [ (hexChars.find(vString[0].tochar())*16) + hexChars.find(vString[1].tochar()),
            (hexChars.find(vString[2].tochar())*16) + hexChars.find(vString[3].tochar()),
            (hexChars.find(vString[4].tochar())*16) + hexChars.find(vString[5].tochar()) ];
}

// Just return the existing LED colors
return [led_r, led_g, led_b];

}

function RGB2Hex(r,g,b)
{
return format(r,"%02X") + format(g,"%02X") + format(b,"%02X");
}

5

Ooh, thats a really neat way of doing it. Thanks!