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[components/lwp]add doxygen comment for lwp avl implementation.

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ligr
2025-09-22 19:52:32 +08:00
committed by R b b666
parent ef354df2e3
commit 0785e224ce
2 changed files with 78 additions and 8 deletions
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71
components/lwp/lwp_avl.c
View File

@@ -1,5 +1,5 @@
/*
* Copyright (c) 2006-2020, RT-Thread Development Team
* Copyright (c) 2006-2025 RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
@@ -10,6 +10,19 @@
#include <rtthread.h>
#include <lwp_avl.h>
/**
* @brief Rebalances an AVL tree after insertion or deletion
*
* @param[in,out] nodeplaces_ptr Pointer to stack of node pointers that need rebalancing
* @param[in] count Number of nodes in the stack that need rebalancing
*
* @note This function performs AVL tree rebalancing by checking and correcting height imbalances
* between left and right subtrees. It handles:
* - Left-left case (single right rotation)
* - Left-right case (double rotation: left then right)
* - Right-right case (single left rotation)
* - Right-left case (double rotation: right then left)
*/
static void lwp_avl_rebalance(struct lwp_avl_struct ***nodeplaces_ptr, int count)
{
for (; count > 0; count--)
@@ -76,6 +89,18 @@ static void lwp_avl_rebalance(struct lwp_avl_struct ***nodeplaces_ptr, int count
}
}
/**
* @brief Removes a node from an AVL tree while maintaining balance
*
* @param[in] node_to_delete The node to be removed from the AVL tree
* @param[in,out] ptree Pointer to the root node pointer of the AVL tree
*
* @note This function removes the specified node from the AVL tree and performs
* necessary rebalancing operations. It handles both cases where the node
* has no left child (simple removal) and where it has a left child (finding
* the rightmost node in the left subtree as replacement).
* It uses a stack to track the removal path for rebalancing.
*/
void lwp_avl_remove(struct lwp_avl_struct *node_to_delete, struct lwp_avl_struct **ptree)
{
avl_key_t key = node_to_delete->avl_key;
@@ -132,6 +157,14 @@ void lwp_avl_remove(struct lwp_avl_struct *node_to_delete, struct lwp_avl_struct
lwp_avl_rebalance(stack_ptr, stack_count);
}
/**
* @brief Inserts a new node into an AVL tree while maintaining balance
*
* @param[in] new_node The new node to be inserted into the AVL tree
* @param[in,out] ptree Pointer to the root node pointer of the AVL tree
*
* @note Uses a stack to track the insertion path for rebalancing
*/
void lwp_avl_insert(struct lwp_avl_struct *new_node, struct lwp_avl_struct **ptree)
{
avl_key_t key = new_node->avl_key;
@@ -158,6 +191,18 @@ void lwp_avl_insert(struct lwp_avl_struct *new_node, struct lwp_avl_struct **ptr
lwp_avl_rebalance(stack_ptr, stack_count);
}
/**
* @brief Finds a node in an AVL tree by key
*
* @param[in] key The key to search for in the AVL tree
* @param[in] ptree Pointer to the root node of the AVL tree
*
* @return struct lwp_avl_struct* Pointer to the found node, or NULL if not found
*
* @note This function searches the AVL tree for a node with the specified key.
* It performs a standard binary search by comparing keys and traversing
* left or right subtrees accordingly.
*/
struct lwp_avl_struct *lwp_avl_find(avl_key_t key, struct lwp_avl_struct *ptree)
{
for (;;)
@@ -176,6 +221,19 @@ struct lwp_avl_struct *lwp_avl_find(avl_key_t key, struct lwp_avl_struct *ptree)
return ptree;
}
/**
* @brief Recursively traverses an AVL tree and applies a function to each node
*
* @param[in] ptree Pointer to the root node of the AVL tree
* @param[in] fun Callback function to apply to each node
* @param[in,out] arg Additional argument passed to the callback function
*
* @return int Returns the last result from the callback function (0 if all nodes processed)
*
* @note This function performs an in-order traversal of the AVL tree, applying the
* provided callback function to each node. The traversal can be stopped early
* if the callback returns a non-zero value.
*/
int lwp_avl_traversal(struct lwp_avl_struct *ptree, int (*fun)(struct lwp_avl_struct *, void *), void *arg)
{
int ret;
@@ -208,6 +266,16 @@ int lwp_avl_traversal(struct lwp_avl_struct *ptree, int (*fun)(struct lwp_avl_st
return ret;
}
/**
* @brief Finds the first (leftmost) node in an AVL tree
*
* @param[in] ptree Pointer to the root node of the AVL tree
*
* @return struct lwp_avl_struct* Pointer to the leftmost node, or NULL if tree is empty
*
* @note This function traverses the AVL tree to find the leftmost node, which represents
* the minimum element in the tree. It's commonly used for ordered traversal starting point.
*/
rt_weak struct lwp_avl_struct* lwp_map_find_first(struct lwp_avl_struct* ptree)
{
if (ptree == AVL_EMPTY)
@@ -224,4 +292,3 @@ rt_weak struct lwp_avl_struct* lwp_map_find_first(struct lwp_avl_struct* ptree)
}
return ptree;
}

15
components/lwp/lwp_avl.h
View File

@@ -1,5 +1,5 @@
/*
* Copyright (c) 2006-2020, RT-Thread Development Team
* Copyright (c) 2006-2025 RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
@@ -24,13 +24,16 @@ extern "C" {
#define avl_maxheight 32
#define heightof(tree) ((tree) == AVL_EMPTY ? 0 : (tree)->avl_height)
/**
* @brief AVL tree node structure for thread ID (tid) or Process ID (pid) management
*/
struct lwp_avl_struct
{
struct lwp_avl_struct *avl_left;
struct lwp_avl_struct *avl_right;
int avl_height;
avl_key_t avl_key;
void *data;
struct lwp_avl_struct *avl_left; /**< Pointer to left child node */
struct lwp_avl_struct *avl_right; /**< Pointer to right child node */
int avl_height; /**< Height of the node in the AVL tree */
avl_key_t avl_key; /**< Key value used for AVL tree node comparison */
void *data; /**< Pointer to associated data */
};
void lwp_avl_remove(struct lwp_avl_struct * node_to_delete, struct lwp_avl_struct ** ptree);