objective c - Convert NSValue to NSData and back again, with the correct type -


i able convert objective-c object, such nsarray or uiimage nsdata object, can use write disk. first converted them nsvalue, planned on converting nsdata. this question provided part of answer, working nsnumber, didn't have need convert nsvalue.

i have seen other questions such this one relies on nskeyedarchiver, steer away due vast size inflation occurs.

therefore code @ moment encoding nsdata object nsvalue, first question, follows:

+(nsdata*) datawithvalue:(nsvalue*)value {      nsuinteger size;      const char* encoding = [value objctype];     nsgetsizeandalignment(encoding, &size, null);      void* ptr = malloc(size);     [value getvalue:ptr];     nsdata* data = [nsdata datawithbytes:ptr length:size];     free(ptr);      return data; }

my question how go decoding nsdata object has been encoded in manner , original objctype nsvalue?

i assume using along these lines

[nsvalue valuewithbytes:[data bytes] objctype:typehere];

how type information?

use nskeyedarchiver save items , nskeyedunarchiver restore object. object must conform nscoding , in case of collection contained items must conform nscoding.

see apple documentation of nskeyedarchiver , nscoder


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