Long lasting hash from string on iOS and Android

I have a requirement for hash strings for a long time on both iOS and Android. Be sure to have the same results for the same row on both platforms.

The code I'm using on iOS:

+ (long long)hashString:(NSString *)stringToHash
{
     if (stringToHash.length == 0)
        return -1;

     //cr: resolve the warnings here
     const unsigned char* str = [stringToHash UTF8String];
     int hash = 5381;
     int c;
     while ((c = *str++)) hash = ((hash << 5) + hash) + c;
     bool isNegative = (hash < 0);
     hash = abs(hash);
     long long lhash = (long)hash;
     long long mask = 1;
     mask <<= 31;
     if (isNegative) lhash |= mask;
     return lhash;
}

      

        
        
        
      

    

For Android I am using this code (c code converted to Java):

public static long doHash(String value) {  
       if (TextUtils.isEmpty(value)) {
           return -1;
       }

       int hash = 5381;               
       for (int i = 0; i < value.length(); i++) {
           hash = ((hash << 5) + hash) + value.charAt(i);
       }     

       boolean isNegative = (hash < 0);
       hash = Math.abs(hash);

       long lHash = (long) hash;
       long mask = 1;       
       mask <<= 31;       
       if (isNegative) { lHash |= mask; }     

       return lHash;
 }

      

        
        
        
      

    

In general everything works fine, but sometimes in Android I have a problem where I get a different hash value for the same string.

For example:

            doHash("Saved Tap"); returns – 3598946179
            doHash("Saved Tap"); returns – 3433737033

      

        
        
        
      

    

I am getting these values ​​from logs from devices there ... Can't reproduce on devices that I have.

Does anyone see bugs in Java code that could cause this problem? Could it be Java version or Android version?

Thank,