package pers.cz.tools;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.util.Arrays;
/**
 * @program: Reids
 * @description: 擴(kuò)展ByteBuffer,提供多次標(biāo)記的功能。
 * @author: Cheng Zhi
 * @create: 2023-04-13 20:23
 **/
public class JefByteBuffer {
    /**
     * 保存所有的標(biāo)記點(diǎn)
     */
    private int[] markPocket = new int[16];
    ByteBuffer byteBuffer;
    private int index = 0;
    public JefByteBuffer(int capacity, boolean isUseLocalMem) {
        if (isUseLocalMem) {
            byteBuffer = ByteBuffer.allocateDirect(capacity);
        } else {
            byteBuffer =  ByteBuffer.allocate(capacity);
        }
    }
    public JefByteBuffer(ByteBuffer byteBuffer) {
        this.byteBuffer = byteBuffer;
    }
    /**
     * 切換模式
     */
    public Buffer flip() {
       return byteBuffer.flip();
    }
    public char read() {
        return (char) byteBuffer.get();
    }
    public void unread() {
        int position = byteBuffer.position();
        byteBuffer.position(position - 1);
    }
    public byte get() {
        return byteBuffer.get();
    }
    public void put(byte[] src) {
        byteBuffer.put(src);
    }
    public void put(byte bi) {
        byteBuffer.put(bi);
    }
    public void clear() {
        byteBuffer.clear();
    }
    public boolean isEnd() {
        int current = byteBuffer.position();
        int end = byteBuffer.limit();
        if (current == end) {
            return true;
        }
        return false;
    }
    /**
     * 打標(biāo)記
     */
    public void mark() {
        int mark = byteBuffer.position();
        ensureCapacityInternal();
        markPocket[index] = mark;
        index ++;
    }
    /**
     * 去除標(biāo)記
     */
    public void unmark() {
        index --;
        markPocket[index] = 0;
    }
    /**
     * 重置
     */
    public void reset() {
        index --;
        if (index < 0) {
            return;
        }
        int mark = markPocket[index];
        if (mark < 0) {
            return;
        }
        byteBuffer.position(mark);
    }
    /**
     * 為markPocket擴(kuò)容
     */
    private void ensureCapacityInternal() {
        int oldCapacity = markPocket.length;
        if (index >= oldCapacity) {
            int newCapacity = oldCapacity + (oldCapacity >> 1);
            // minCapacity is usually close to size, so this is a win:
            markPocket = Arrays.copyOf(markPocket, newCapacity);
        }
    }
}

public static void test2() {
        JefByteBuffer jefByteBuffer = new JefByteBuffer(100);
        jefByteBuffer.put(new byte[] {'1','2','3','4','5','6','7','8','9','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t'});
        jefByteBuffer.flip();
        for (int i=1; i<21; i++) {
            if (i == 1) {
                jefByteBuffer.mark();
            }
            if (i == 3) {
                jefByteBuffer.mark();
            }
            if (i == 5) {
                jefByteBuffer.mark();
            }
            if (i == 7) {
                jefByteBuffer.mark();
            }
            if (i == 9) {
                jefByteBuffer.mark();
            }
            if (i == 10) {
                jefByteBuffer.unmark();
            }
            if (i == 11) {
                //jefByteBuffer.unmark();
                // 這里將回到i=7的標(biāo)記點(diǎn)
                jefByteBuffer.reset();
            }
/*            if (i ==8) {
                jefByteBuffer.reset();
            }*/
            char b = (char) jefByteBuffer.read();
            jefByteBuffer.unread();
            System.out.println(b);
        }
    }