mirror of
https://github.com/DragonOS-Community/DragonOS.git
synced 2025-06-09 19:36:47 +00:00
234 lines
6.0 KiB
C
234 lines
6.0 KiB
C
#include <common/bitree.h>
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#include <mm/slab.h>
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#include <common/errno.h>
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#include <common/kfifo.h>
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#include <common/string.h>
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#include <debug/bug.h>
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#define smaller(root, a, b) (root->cmp((a)->value, (b)->value) == -1)
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#define equal(root, a, b) (root->cmp((a)->value, (b)->value) == 0)
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#define greater(root, a, b) (root->cmp((a)->value, (b)->value) == 1)
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/**
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* @brief 创建二叉搜索树
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*
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* @param node 根节点
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* @param cmp 比较函数
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* @param release 用来释放结点的value的函数
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* @return struct bt_root_t* 树根结构体
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*/
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struct bt_root_t *bt_create_tree(struct bt_node_t *node, int (*cmp)(void *a, void *b), int (*release)(void *value))
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{
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if (node == NULL || cmp == NULL)
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return (void*)-EINVAL;
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struct bt_root_t *root = (struct bt_root_t *)kmalloc(sizeof(struct bt_root_t), 0);
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memset((void *)root, 0, sizeof(struct bt_root_t));
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root->bt_node = node;
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root->cmp = cmp;
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root->release = release;
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root->size = (node == NULL) ? 0 : 1;
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return root;
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}
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/**
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* @brief 创建结点
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*
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* @param left 左子节点
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* @param right 右子节点
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* @param value 当前节点的值
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* @return struct bt_node_t*
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*/
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struct bt_node_t *bt_create_node(struct bt_node_t *left, struct bt_node_t *right, struct bt_node_t *parent, void *value)
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{
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struct bt_node_t *node = (struct bt_node_t *)kmalloc(sizeof(struct bt_node_t), 0);
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FAIL_ON_TO(node == NULL, nomem);
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memset((void *)node, 0, sizeof(struct bt_node_t));
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node->left = left;
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node->right = right;
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node->value = value;
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node->parent = parent;
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return node;
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nomem:;
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return (void*)-ENOMEM;
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}
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/**
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* @brief 插入结点
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*
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* @param root 树根结点
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* @param value 待插入结点的值
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* @return int 返回码
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*/
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int bt_insert(struct bt_root_t *root, void *value)
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{
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if (root == NULL)
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return -EINVAL;
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struct bt_node_t *this_node = root->bt_node;
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struct bt_node_t *last_node = NULL;
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struct bt_node_t *insert_node = bt_create_node(NULL, NULL, NULL, value);
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FAIL_ON_TO((uint64_t)insert_node == (uint64_t)(-ENOMEM), failed);
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while (this_node != NULL)
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{
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last_node = this_node;
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if (smaller(root, insert_node, this_node))
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this_node = this_node->left;
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else
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this_node = this_node->right;
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}
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insert_node->parent = last_node;
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if (unlikely(last_node == NULL))
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root->bt_node = insert_node;
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else
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{
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if (smaller(root, insert_node, last_node))
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last_node->left = insert_node;
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else
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last_node->right = insert_node;
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}
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++root->size;
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return 0;
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failed:;
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return -ENOMEM;
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}
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/**
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* @brief 搜索值为value的结点
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*
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* @param value 值
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* @param ret_addr 返回的结点基地址
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* @return int 错误码
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*/
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int bt_query(struct bt_root_t *root, void *value, uint64_t *ret_addr)
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{
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struct bt_node_t *this_node = root->bt_node;
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struct bt_node_t tmp_node = {0};
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tmp_node.value = value;
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// 如果返回地址为0
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if (ret_addr == NULL)
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return -EINVAL;
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while (this_node != NULL && !equal(root, this_node, &tmp_node))
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{
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if (smaller(root, &tmp_node, this_node))
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this_node = this_node->left;
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else
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this_node = this_node->right;
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}
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if (this_node != NULL && equal(root, this_node, &tmp_node))
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{
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*ret_addr = (uint64_t)this_node;
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return 0;
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}
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else
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{
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// 找不到则返回-1,且addr设为0
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*ret_addr = NULL;
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return -1;
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}
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}
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static struct bt_node_t *bt_get_minimum(struct bt_node_t *this_node)
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{
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while (this_node->left != NULL)
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this_node = this_node->left;
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return this_node;
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}
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/**
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* @brief 删除结点
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*
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* @param root 树根
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* @param value 待删除结点的值
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* @return int 返回码
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*/
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int bt_delete(struct bt_root_t *root, void *value)
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{
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uint64_t tmp_addr;
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int retval;
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// 寻找待删除结点
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retval = bt_query(root, value, &tmp_addr);
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if (retval != 0 || tmp_addr == NULL)
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return retval;
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struct bt_node_t *this_node = (struct bt_node_t *)tmp_addr;
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struct bt_node_t *to_delete = NULL, *to_delete_son = NULL;
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if (this_node->left == NULL || this_node->right == NULL)
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to_delete = this_node;
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else
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{
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to_delete = bt_get_minimum(this_node->right);
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// 释放要被删除的值,并把下一个结点的值替换上来
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root->release(this_node->value);
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this_node->value = to_delete->value;
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}
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if (to_delete->left != NULL)
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to_delete_son = to_delete->left;
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else
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to_delete_son = to_delete->right;
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if (to_delete_son != NULL)
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to_delete_son->parent = to_delete->parent;
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if (to_delete->parent == NULL)
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root->bt_node = to_delete_son;
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else
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{
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if (to_delete->parent->left == to_delete)
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to_delete->parent->left = to_delete_son;
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else
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to_delete->parent->right = to_delete_son;
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}
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--root->size;
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// 释放最终要删除的结点的对象
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kfree(to_delete);
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}
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/**
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* @brief 释放整个二叉搜索树
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*
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* @param root 树的根节点
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* @return int 错误码
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*/
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int bt_destroy_tree(struct bt_root_t *root)
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{
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// 新建一个kfifo缓冲区,将指向结点的指针存入fifo队列
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// 注:为了将指针指向的地址存入队列,我们需要对指针取地址
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struct kfifo_t fifo;
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kfifo_alloc(&fifo, ((root->size + 1) / 2) * sizeof(struct bt_node_t *), 0);
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kfifo_in(&fifo, (void *)&(root->bt_node), sizeof(struct bt_node_t *));
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// bfs
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while (!kfifo_empty(&fifo))
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{
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// 取出队列头部的结点指针
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struct bt_node_t *nd;
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int count = kfifo_out(&fifo, &nd, sizeof(uint64_t));
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// 将子节点加入队列
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if (nd->left != NULL)
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kfifo_in(&fifo, (void *)&(nd->left), sizeof(struct bt_node_t *));
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if (nd->right != NULL)
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kfifo_in(&fifo, (void *)&(nd->right), sizeof(struct bt_node_t *));
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// 销毁当前节点
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root->release(nd->value);
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kfree(nd);
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}
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kfifo_free_alloc(&fifo);
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return 0;
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} |