C语言宏定义实现的代码，类似uthash

以下是一个使用 C 语言宏定义实现的哈希表（类似于 uthash）的示例代码：

#include <stdio.h>
#include <stdlib.h>

/* 定义哈希表结构体 */
#define HASH_TABLE(name, key_type, value_type) \
    typedef struct name##_entry { \
        key_type key; \
        value_type value; \
        struct name##_entry *next; \
    } name##_entry; \
    typedef struct { \
        int size; \
        name##_entry **table; \
    } name

/* 初始化哈希表 */
#define HASH_TABLE_INIT(table, size) \
    do { \
        (table)->size = size; \
        (table)->table = calloc(size, sizeof(*(table)->table)); \
    } while (0)

/* 释放哈希表 */
#define HASH_TABLE_FREE(table) \
    do { \
        int i; \
        for (i = 0; i < (table)->size; i++) { \
            name##_entry *entry = (table)->table[i]; \
            while (entry) { \
                name##_entry *next = entry->next; \
                free(entry); \
                entry = next; \
            } \
        } \
        free((table)->table); \
    } while (0)

/* 查找键对应的值 */
#define HASH_TABLE_GET(table, key, default) \
    ({ \
        int index = (key) % (table)->size; \
        name##_entry *entry = (table)->table[index]; \
        while (entry) { \
            if ((entry)->key == (key)) { \
                break; \
            } \
            entry = entry->next; \
        } \
        (entry) ? (entry)->value : (default); \
    })

/* 设置键对应的值 */
#define HASH_TABLE_SET(table, key, value) \
    do { \
        int index = (key) % (table)->size; \
        name##_entry *entry = (table)->table[index]; \
        while (entry) { \
            if ((entry)->key == (key)) { \
                (entry)->value = (value); \
                break; \
            } \
            entry = entry->next; \
        } \
        if (!entry) { \
            entry = calloc(1, sizeof(*entry)); \
            entry->key = (key); \
            entry->value = (value); \
            entry->next = (table)->table[index]; \
            (table)->table[index] = entry; \
        } \
    } while (0)

/* 删除键对应的值 */
#define HASH_TABLE_DEL(table, key) \
    do { \
        int index = (key) % (table)->size; \
        name##_entry *entry = (table)->table[index]; \
        name##_entry *prev = NULL; \
        while (entry) { \
            if ((entry)->key == (key)) { \
                if (prev) { \
                    prev->next = entry->next; \
                } else { \
                    (table)->table[index] = entry->next; \
                } \
                free(entry); \
                break; \
            } \
            prev = entry; \
            entry = entry->next; \
        } \
    } while (0)

/* 示例用法 */
HASH_TABLE(my_hash_table, int, char *);

int main() {
    my_hash_table table;
    HASH_TABLE_INIT(&table, 10);

    HASH_TABLE_SET(&table, 1, "one");
    HASH_TABLE_SET(&table, 2, "two");
    HASH_TABLE_SET(&table, 3, "three");

    printf("%s\n", HASH_TABLE_GET(&table, 1, "not found"));
    printf("%s\n", HASH_TABLE_GET(&table, 2, "not found"));
    printf("%s\n", HASH_TABLE_GET(&table, 3, "not found"));

    HASH_TABLE_DEL(&table, 2);

    printf("%s\n", HASH_TABLE_GET(&table, 1, "not found"));
    printf("%s\n", HASH_TABLE_GET(&table, 2, "not found"));
    printf("%s\n", HASH_TABLE_GET(&table, 3, "not found"));

    HASH_TABLE_FREE(&table);

    return 0;
}

这个示例代码定义了一个名为 `my_hash_table` 的哈希表类型，其中键的类型为 `int`，值的类型为 `char *`。通过使用宏定义来实现，可以方便地在其他代码中使用这个哈希表类型，并调用宏定义中定义的函数来操作哈希表。