exc_breakpoint while JSON parsing - iphone

Question

I want to parse many JSON strings. Here is the code:
while(stations.count > 0) {
NSString*string = [[[NSString alloc] initWithString:[stations objectAtIndex:0]] retain];
NSMutableDictionary*dic = [[[NSMutableDictionary alloc]init]retain];
NSData*data = [[[NSData alloc] initWithData:[string dataUsingEncoding:NSUTF8StringEncoding]]retain];
NSMutableDictionary* pars = [[NSMutableDictionary alloc]initWithDictionary:[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil]];
[dic setObject:[NSString stringWithString:[pars objectForKey:#"nm"]] forKey:#"nm"];
[dic setObject:[NSString stringWithString:[pars objectForKey:#"btr"]] forKey:#"btr"];
[dic setObject:[NSString stringWithString:[pars objectForKey:#"id"]] forKey:#"id"];
[dic setObject:[NSString stringWithString:[pars objectForKey:#"cntr"]] forKey:#"cntr"];
[dic setObject:[NSString stringWithString:[pars objectForKey:#"gnr"]] forKey:#"gnr"];
[pars release];
#try {
[parsedData addObject:[NSDictionary dictionaryWithDictionary:dic]];
}
#catch (NSException* exc) {
NSLog(#"%#, %#", exc.description, exc.reason);
}
[dic release];
[data release];
[string release];
[stations removeObjectAtIndex:0];
if (i%1000==0) {
NSLog(#"nnnn %i %i", parsedData.count, stations.count);
}
i++;
float k = count;
k = (i + 1)/k;
[self performSelectorOnMainThread:#selector(increaseProgress:) withObject:[NSNumber numberWithFloat:k] waitUntilDone:YES];
}
On adding (usually but not every time) string to array I get error:
exc_breakpoint (code=exc_i386_bpt
and:
GuardMalloc[Radiocent new try-1820]: Failed to VM allocate 68752 bytes
GuardMalloc[Radiocent new try-1820]: Explicitly trapping into debugger!!!
Stations array is pretty big... about 60000 strings.

Answer 1

First of all when you alloc you don't need to retain as retain count is already +1.
NSMutableDictionary *dic = [[NSMutableDictionary alloc] init];
Not
NSMutableDictionary*dic = [[[NSMutableDictionary alloc]init]retain];
Below line already returs mutable dictionary so you don't have to create a new dictionary out of that and if you want to change then just call a - mutableCopy on it.
NSMutableDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
or to create a copy:
NSMutableDictionary *dictionary = [[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil] mutableCopy];
If stations is JSON string then for all stations do this:
NSData *data = [JSONString dataUsingEncoding:NSUTF8StringEncoding];
NSArray *stationsArray = [[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil] mutableCopy];
for (NSDictionary *stationDic in stationArray)
{
// This will iterate over each station dictionary in the station array
// Do your stuff here ...
}
For your example: (I have added \" to escape the double quotes, you don't have to)
Placed square brackets around your example this make it an array and you can iterate through each using the given code below. (Add only if they are not there)
NSString *example = #"[{\"id\":\"02AB99\",\"btr\":\"24\",\"cntr\":\"461E\",\"gnr\":\"8A51\",\"nm\":\"88.3 Fm Radio Q Jogjakarta\"}, {\"id\":\"026058\",\"btr\":\"160\",\"cntr\":\"461E\",\"gnr\":\"8A7B\",\"nm\":\"88.3 The Dog\"}, {\"id\":\"0300D2\",\"btr\":\"55 64\",\"cntr\":\"461C\",\"gnr\":\"8A75\",\"nm\":\"88.3 The Wind\"}, {\"id\":\"0159E6\",\"btr\":\"128\",\"cntr\":\"4610\",\"gnr\":\"8A6C\",\"nm\":\"88.30 Z Fm Radio Word Online\"}]";
NSError *error = nil;
NSArray *stationArray = [NSJSONSerialization JSONObjectWithData:[example dataUsingEncoding:NSUTF8StringEncoding] options:NSJSONReadingAllowFragments error:&error];
if (!error)
{
for (NSDictionary *stationDic in stationArray)
{
NSLog(#"\nName: %# \nDump: \n%#", [stationDic valueForKey:#"nm"], stationDic);
}
}