/**
* Returns the long associated with the String or 0 if there is no long associated with the
* string. If newValue is not equal to 0 then this becomes the new value associated with the
* string.
*
* @param str the String.
* @param newValue if not equal to 0, the new value to be associated with the string.
* @return the long currently associated with the String or 0 if there is no long associated with
* the string.
* @throws IOException if an I/O error occurs or the hash table is full.
*/
public long getAndPut(String str, long newValue) throws IOException {
if (str == null) {
throw new IllegalArgumentException("str is null");
}
if (newValue == 0) {
Long l = cache.get(str);
if (l != null) {
return l.longValue();
}
}
int hashCode = str.hashCode();
int startBucket = calcBucket(hashCode);
int bucket = startBucket;
long value;
// Try buckets until we find the correct string or an empty bucket.
while ((value = getValue(bucket)) != 0) {
// Check the hash code.
long offset = (long) bucket * 4;
if (hashCode == hashFile.getInt(offset)) {
// Fetch the string and compare with the target string.
String bucketStr = readString(hashFile.getUInt(offset + 1));
if (str.equals(bucketStr)) {
if (newValue != 0) {
hashFile.putLong((long) bucket * 2 + 1, newValue);
// Add the new value to the cache.
cache.put(str, newValue);
} else {
// Add the value to the cache.
cache.put(str, value);
}
return value;
}
}
// Try the next bucket.
bucket = (bucket + 1) % nrBuckets;
if (bucket == startBucket) {
throw new IOException("Hash table full");
}
}
if (newValue != 0) {
// Add the new value to the cache.
cache.put(str, newValue);
// Add a new hash bucket.
long bucketOffset = (long) bucket * 4;
hashFile.putInt(bucketOffset, hashCode);
hashFile.putUInt(bucketOffset + 1, writeString(str));
hashFile.putLong((long) bucket * 2 + 1, newValue);
++nrUsedBuckets;
if (nrUsedBuckets >= (int) (nrBuckets * REHASH_LIMIT)) {
rehash(findPrime(nrBuckets));
}
}
return 0;
}
