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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.buffer;

import io.netty.util.internal.StringUtil;

final class PoolChunkList {
    private final PoolArena arena;
    private final PoolChunkList nextList;
    PoolChunkList prevList;

    private final int minUsage;
    private final int maxUsage;

    private PoolChunk head;

    // TODO: Test if adding padding helps under contention
    //private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;

    PoolChunkList(PoolArena arena, PoolChunkList nextList, int minUsage, int maxUsage) {
        this.arena = arena;
        this.nextList = nextList;
        this.minUsage = minUsage;
        this.maxUsage = maxUsage;
    }

    boolean allocate(PooledByteBuf buf, int reqCapacity, int normCapacity) {
        if (head == null) {
            return false;
        }

        for (PoolChunk cur = head;;) {
            long handle = cur.allocate(normCapacity);
            if (handle < 0) {
                cur = cur.next;
                if (cur == null) {
                    return false;
                }
            } else {
                cur.initBuf(buf, handle, reqCapacity);
                if (cur.usage() >= maxUsage) {
                    remove(cur);
                    nextList.add(cur);
                }
                return true;
            }
        }
    }

    void free(PoolChunk chunk, long handle) {
        chunk.free(handle);
        if (chunk.usage() < minUsage) {
            remove(chunk);
            if (prevList == null) {
                assert chunk.usage() == 0;
                arena.destroyChunk(chunk);
            } else {
                prevList.add(chunk);
            }
        }
    }

    void add(PoolChunk chunk) {
        if (chunk.usage() >= maxUsage) {
            nextList.add(chunk);
            return;
        }

        chunk.parent = this;
        if (head == null) {
            head = chunk;
            chunk.prev = null;
            chunk.next = null;
        } else {
            chunk.prev = null;
            chunk.next = head;
            head.prev = chunk;
            head = chunk;
        }
    }

    private void remove(PoolChunk cur) {
        if (cur == head) {
            head = cur.next;
            if (head != null) {
                head.prev = null;
            }
        } else {
            PoolChunk next = cur.next;
            cur.prev.next = next;
            if (next != null) {
                next.prev = cur.prev;
            }
        }
    }

    @Override
    public String toString() {
        if (head == null) {
            return "none";
        }

        StringBuilder buf = new StringBuilder();
        for (PoolChunk cur = head;;) {
            buf.append(cur);
            cur = cur.next;
            if (cur == null) {
                break;
            }
            buf.append(StringUtil.NEWLINE);
        }

        return buf.toString();
    }
}