Question

I’m having issues with converting a hexadecimal number to an NSNumber. I tried a ton of things, but I can’t seem to work it out.

With something like the following, how can I get an NSNumber?

Byte test[4] = {0x00, 0x00, 0x1D, 0x7A}; // Expected result is 7546
NSData * testData = [NSData dataWithBytes:&test length:4];
// NSNumber = ...

Answer 1

NSScanner has the following methods

- (BOOL)scanHexFloat:(float *)result
- (BOOL)scanHexDouble:(double *)result
- (BOOL)scanHexLongLong:(unsigned long long *)result
- (BOOL)scanHexInt:(unsigned *)intValue

so you can scan a hex NSString representation. Discussion for the last one:

The hexadecimal integer representation may optionally be preceded by
0x or 0X. Skips past excess digits in the case of overflow, so the
receiver’s position is past the entire hexadecimal representation.
Invoke this method with NULL as intValue to simply scan past a
hexadecimal integer representation.