编码和解码GameState类问题

Question

I have a class named HeroState that is an inheritance from another class named CharacterProperties that contains armorId, headId, earsId and some other common values to create a character. In this new class I have declared on the header. (It is the class in charge of the players progress , by saying that It's a singleton)

    @interface HeroState : CharacterProperties <NSCoding>  {
    ControlsType controlsType;
    characterJob charJob;
    MonsterJob monsterJob;
    } 


@property MonsterJob monsterJob;
@property characterJob charJob;
@property (readwrite)ControlsType controlsType;

+ (HeroState *) sharedInstance;
- (void)save;

@end

And I have a "database" class in charge of saving and loading the class.

database Header :

#import <Foundation/Foundation.h>

id loadData(NSString * filename);
void saveData(id theData, NSString *filename);

database Implementation :

NSString * pathForFile(NSString *filename) {
    // 1
    NSArray *paths =
    NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                        NSUserDomainMask,
                                        YES);
    // 2
    NSString *documentsDirectory = [paths objectAtIndex:0];
    // 3
    return [documentsDirectory
            stringByAppendingPathComponent:filename];
}

id loadData(NSString * filename) {
    // 4
    NSString *filePath = pathForFile(filename);
    // 5
    if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
        // 6
        NSData *data = [[[NSData alloc]
                         initWithContentsOfFile:filePath] autorelease];
        // 7
        NSKeyedUnarchiver *unarchiver = [[[NSKeyedUnarchiver alloc]
                                          initForReadingWithData:data] autorelease];
        // 8
        id retval = [unarchiver decodeObjectForKey:@"Data"];
        [unarchiver finishDecoding];
        return retval;
    }
    return nil;
}

void saveData(id theData, NSString *filename) {
    // 9
    NSMutableData *data = [[[NSMutableData alloc] init] autorelease];
    // 10
    NSKeyedArchiver *archiver = [[[NSKeyedArchiver alloc]
                                  initForWritingWithMutableData:data] autorelease];
    // 11
    [archiver encodeObject:theData forKey:@"Data"];
    [archiver finishEncoding];
    // 12
    [data writeToFile:pathForFile(filename) atomically:YES];
}

But then when I use it on my HeroClass

+(HeroState*)sharedInstance {
    @synchronized([HeroState class])
    {
        if(!sharedInstance) {
            sharedInstance = [loadData(@"HeroState") retain];
            if (!sharedInstance) {
                [[self alloc] initWithNewStats];
            }
        }
        return sharedInstance;
    }
    return nil;
}

And here for saving

- (void)save {
    saveData(self, @"HeroState");
}

It gives me an error when I try to build it:

Undefined symbols for architecture i386: "loadData(NSString*)", referenced from: +[HeroState sharedInstance] in HeroState.o "saveData(objc_object*, NSString*)", referenced from: -[HeroState save] in HeroState.o ld: symbol(s) not found for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation)

I do have a initWithCoder function and a encodeWithCoder function that stick to the protocols of the NSCoding. So what could be wrong? I had this class as a NSObject inhertied class before and had no problem about it , but when I decided to recreate it being a inheritance of my CharacterProperties class that was an Inheritance of NSObject problems occurred.

I will appreciate any type of help!

Answer 1

Are you certain you wanted to declare these as C functions?

NSString * pathForFile(NSString *filename) {..}
id loadData(NSString * filename) {..}
void saveData(id theData, NSString *filename)  {..}

Perhaps you should rather declare them as static class functions.

+(id) loadData:(NSString *)filename {..}
// similar for the other C functions

And call it accordingly:

sharedInstance = [[HeroState loadData:@"HeroState"] retain];

PS: please start using ARC. There's no reason not to in this day and age.