CODEWITHSUNDEEP
c++hexbit-manipulation
Eternal Learner
Eternal Learner

Reputation: 3870

Bit manipulation Hexadecimal C++

I have an unsigned int and a hex value. I want to be able to check if the unsigned int contains the hex value; e.g: 

unsigned int reason = 0x80020002

#define MAJOR_ERROR_CODE 0x00020000
#define MINOR_ERROR_CODE 0x00000002
#define OPTIONAL_ERROR_CODE 0x80000000

Now as we can see, the variable reason has all of the three #define error code. I need to be able to detect the presence/absence of the hex Error Codes int the variable reason. How do I do it?

Edit 1 : Apologies all, I guess I posted a slightly different question when I tried to simplify it and post. What I have is a couple of Major, Minor and Optional Error codes - For Eg

#define MAJOR_ERROR_CODE_1 0x00020000
#define MAJOR_ERROR_CODE_2 0x00010000
#define MAJOR_ERROR_CODE_3 0x00070000

#define MINOR_ERROR_CODE_1 0x00000002
#define MINOR_ERROR_CODE_2 0x00000004
#define MINOR_ERROR_CODE_3 0x00000006

#define OPTIONAL_ERROR_CODE_1 0x80000000
#define OPTIONAL_ERROR_CODE_2 0x50000000
#define OPTIONAL_ERROR_CODE_3 0x30000000

Now my unsigned int is a combination of these three error codes. Each of these error codes have a unique string and depending on which one of these is present in my variable reason i need to generate the string.

Upvotes: 2

Views: 1788

Answers (5)

sethi
sethi

Reputation: 1889

I am not sure if i got the question correct but looks like can check with & operation

e.g.

((reason & MAJOR_ERROR_CODE) != 0)
{

//Do what you want to do for MAJOR_ERROR_CODE

}

Upvotes: 0

dchhetri
dchhetri

Reputation: 7136

Something like so:

const bool isErrorCodeSet = reason & MAJOR_ERROR_CODE;
//...and so on

You can see this works basically by manual and operation:

  80020002
& 00020000 
------------
  00010000

Upvotes: 0

SubSevn
SubSevn

Reputation: 1028

You are most likely looking for bitwise-AND

C++ info here

Upvotes: 0

Rup
Rup

Reputation: 34418

If these are single bit codes, it's as simple as

 if ((reason & MAJOR_ERROR_CODE) != 0)
 {
     // this is a major error
 }

However I suspect it's actually a mask, e.g.

 #define MAJOR_ERROR_MASK 0x7fff0000
 if ((reason & MAJOR_ERROR_MASK) == MAJOR_ERROR_CODE)
 {
      // this is a major error
 }

Upvotes: 2

Michael Dorgan
Michael Dorgan

Reputation: 12515

By using the binary operator &:

if(reason & MAJOR_ERROR_CODE)
{
    // Do Major Error code...    
}

if(reason & MINOR_ERROR_CODE)
{
    // Do minor Error code...    
}

if(reason & OPTIONAL_ERROR_CODE)
{
    // Do Optional error code...    
}

Upvotes: 3

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