如何安全地将几个对象实例存储在NSFastEnumerationState的额外数组中？
我希望在循环运行时保留这些项目，然后在循环完成时释放。
- (NSUInteger)countByEnumeratingWithState: (NSFastEnumerationState *)state
objects: (__unsafe_unretained id *)stackbuf
count: (NSUInteger)len {
unsigned long days = 0;
id current = nil;
id components = nil;
if (state->state == 0)
{
current = [NSCalendar currentCalendar];
state->mutationsPtr = &state->extra[0];
components = [current components: NSDayCalendarUnit fromDate: _startDate toDate: _endDate options: 0];
days = [components day];
state->extra[0] = days;
state->extra[1] = (uintptr_t)(__bridge void *)current;
state->extra[2] = (uintptr_t)(__bridge void *)components;
} else {
days = state->extra[0];
current = (__bridge NSCalendar *)(void *)(state->extra[1]);
components = (__bridge NSDateComponents *)(void *)(state->extra[2]);
}
NSUInteger count = 0;
if (state->state <= days) {
state->itemsPtr = stackbuf;
while ( (state->state <= days) && (count < len) ) {
[components setDay: state->state];
stackbuf[count] = [current dateByAddingComponents: components toDate: _startDate options: 0];
state->state++;
count++;
}
}
return count;
}
这是NSFastEnumerationState来自 Apple 标头的 的定义：
typedef struct {
unsigned long state;
id __unsafe_unretained *itemsPtr;
unsigned long *mutationsPtr;
unsigned long extra[5];
} NSFastEnumerationState;