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package cn.handyplus.lib.core;

import java.util.HashMap;

/**
 * Map工具类
 *
 * @author handy
 * @since 3.7.2
 */
public class MapUtil {

    private MapUtil() {
    }

    private final static Integer MIN_EXPECTED_SIZE = 3;

    /**
     * 预期大小的hashMap
     *
     * @param expectedSize 预期大小
     * @param           key类型
     * @param           值类型
     * @return HashMap
     */
    public static  HashMap newHashMapWithExpectedSize(int expectedSize) {
        return new HashMap<>(capacity(expectedSize));
    }

    public static  HashMap of() {
        return new HashMap<>(capacity(0));
    }

    public static  HashMap of(K k1, V v1) {
        return new HashMap(capacity(1)) {{
            put(k1, v1);
        }};
    }

    public static  HashMap of(K k1, V v1, K k2, V v2) {
        return new HashMap(capacity(1)) {{
            put(k1, v1);
            put(k2, v2);
        }};
    }

    public static  HashMap of(K k1, V v1, K k2, V v2, K k3, V v3) {
        return new HashMap(capacity(1)) {{
            put(k1, v1);
            put(k2, v2);
            put(k3, v3);
        }};
    }

    public static  HashMap of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
        return new HashMap(capacity(1)) {{
            put(k1, v1);
            put(k2, v2);
            put(k3, v3);
            put(k4, v4);
        }};
    }

    public static  HashMap of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
        return new HashMap(capacity(1)) {{
            put(k1, v1);
            put(k2, v2);
            put(k3, v3);
            put(k4, v4);
            put(k5, v5);
        }};
    }

    /**
     * 容量
     *
     * @param expectedSize 预期大小
     * @return 容量
     */
    private static int capacity(int expectedSize) {
        // 负数判断
        if (expectedSize < 0) {
            expectedSize = 0;
        }
        // 小于3直接+1
        if (expectedSize < MIN_EXPECTED_SIZE) {
            return expectedSize + 1;
        }
        // 进行计算
        return expectedSize < 1073741824 ? (int) ((float) expectedSize / 0.75F + 1.0F) : Integer.MAX_VALUE;
    }

}