NSInteger splitting

Scripting Forums AppleScriptObjC and Xcode
#1

Hello,

I never did this in ObjC and wish to know if it is possible, and how:

I have a 64-bit NSInteger. I want to store two values in it, using the “low” and the “hi” 32-bit words.

I couldn’t find the answer (but maybe I looked at the wrong place)

Thanks!

#2

Hi,

first of all, consider that NSInteger is 32-bit in 32-bit environment.
Better use a type like int32_t


int64_t value = 17179877376;
int32_t high = value >> 32; // 4
int32_t low = value; // 8192
#3

Stefan,

Is that true if the project is targeting a 64bits environment?

#4

If the project is compiled only for 64-bit then NSInteger is 64-bit

to combine two 32-bit values (low high) to one 64-bit use this


int32_t high = 4;
int32_t low = 8192;
    
int64_t high64 = (int64_t)high;
int64_t newValue = (high64 <<= 32) + (int64_t)low; // 17179877376
#5

Are int32_t, int16_t, int8_t types machine independent?
Note: my integer has to store [0…15][0…15] in its two words, they could be bytes. But the original number has to be coerced first (it will never exceed 15 in hi or low “parts”)

#6

Yes, Apple recommends to use these types for a fixed width

PS: [0…15][0…15] is actually a 32-bit value with two 16-bit parts

#7

not if you use unsigned char/__uint8_t then a single byte will do the trick

#8

Right, but I assumed a signed value because of the mentioned NSInteger in the first post