iphone/ipad memory leak from NSString assigned to itself

Question

I have two leaks shown by the instruments tool. I have looked around on google but I haven't seen exactly my problem on there.

Problem #1:

self.wallText = [[text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];

I have tried various configurations of the above line but all leak. I need to do both those trimming operations. 'text' is declared with either @"" or stringWithFormat.

My other issue is with the following line:

    NSString * value = [elements objectAtIndex:i+1];
if ([value length] >= 2 && [[value substringToIndex:2] isEqualToString:@"S_"]){
   value = [value substringFromIndex:2]; // LEAK HERE
    }

I need to get all of the string except for the first 2 characters so I don't know how I could release it first or something... if that is indeed what I should be doing.

I could get away wtih leaks before with previous projects but this one is very memory intensive and I need all the memory I can get!

Any pointers would be greatly appreciated

Answer 1

Did you declare @property (retain) for wallText, did you do [wallText release] in dealloc method?

Double check above things and you will not have leaks any more

For Updated Part:

It is really strange that you have a memory leak there. Because at first, your value points to an autoreleased object then it points to another autoreleased object which I think is fine.

Answer 2

have u use alloc for value. value = [value substringFromIndex:2]; .here now value is referencing to new autorelease string. so u can not release previous object.