Objective-C vs JavaScript loop performance
- by micadelli
I have a PhoneGap mobile application that I need to generate an array of match combinations. In JavaScript side, the code hanged pretty soon when the array of which the combinations are generated from got a bit bigger. So, I thought I'll make a plugin to generate the combinations, passing the array of javascript objects to native side and loop it there.
To my surprise the following codes executes in 150 ms (JavaScript) whereas in native side (Objective-C) it takes ~1000 ms.
Does anyone know any tips for speeding up those executing times? When players exceeds 10, i.e. the length of the array of teams equals 252 it really gets slow. Those execution times mentioned above are for 10 players / 252 teams.
Here's the JavaScript code:
for (i = 0; i < GAME.teams.length; i += 1) {
for (j = i + 1; j < GAME.teams.length; j += 1) {
t1 = GAME.teams[i];
t2 = GAME.teams[j];
if ((t1.mask & t2.mask) === 0) {
GAME.matches.push({
Team1: t1,
Team2: t2
});
}
}
}
... and here's the native code:
NSArray *teams = [[NSArray alloc] initWithArray: [options objectForKey:@"teams"]];
NSMutableArray *t = [[NSMutableArray alloc] init];
int mask_t1;
int mask_t2;
for (NSInteger i = 0; i < [teams count]; i++) {
for (NSInteger j = i + 1; j < [teams count]; j++) {
mask_t1 = [[[teams objectAtIndex:i] objectForKey:@"mask"] intValue];
mask_t2 = [[[teams objectAtIndex:j] objectForKey:@"mask"] intValue];
if ((mask_t1 & mask_t2) == 0) {
[t insertObject:[teams objectAtIndex:i] atIndex:0];
[t insertObject:[teams objectAtIndex:j] atIndex:1];
/*
NSArray *newCombination = [[NSArray alloc] initWithObjects:
[teams objectAtIndex:i],
[teams objectAtIndex:j],
nil];
*/
[combinations addObject:t];
}
}
}
... the array in question (GAME.teams) looks like this:
{
count = 2;
full = 1;
list = (
{
index = 0;
mask = 1;
name = A;
score = 0;
},
{
index = 1;
mask = 2;
name = B;
score = 0;
}
);
mask = 3;
name = A;
},
{
count = 2;
full = 1;
list = (
{
index = 0;
mask = 1;
name = A;
score = 0;
},
{
index = 2;
mask = 4;
name = C;
score = 0;
}
);
mask = 5;
name = A;
},
