使用usedEncoding及big5 encoding轉換

gistfile1.m

NSStringEncoding usedEncoding;
NSError * err;
NSString * k = [NSString stringWithContentsOfFile:path usedEncoding:&usedEncoding error:&err]; 
if (err) {
    NSStringEncoding big5 = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingBig5_HKSCS_1999);
    k = [NSString stringWithContentsOfFile:path encoding:big5 error:&err];
}