/*
 * Copyright 2012-2018 Chronicle Map Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.openhft.chronicle.hash.impl.stage.query;

import net.openhft.chronicle.hash.impl.stage.entry.Alloc;
import net.openhft.chronicle.hash.impl.stage.entry.SegmentStages;
import net.openhft.sg.StageRef;
import net.openhft.sg.Staged;

@Staged
public class QueryAlloc implements Alloc {

    @StageRef
    public SegmentStages s;

    @Override
    public long alloc(int chunks, long prevPos, int prevChunks) {
        long ret = s.allocReturnCode(chunks);
        if (prevPos >= 0)
            s.free(prevPos, prevChunks);
        if (ret >= 0)
            return ret;
        int alreadyAttemptedTier = s.tier;
        s.goToFirstTier();
        while (true) {
            if (s.tier != alreadyAttemptedTier) {
                ret = s.allocReturnCode(chunks);
                if (ret >= 0)
                    return ret;
            }
            s.nextTier();
        }
    }
}
