0

所以我遇到了一个问题，我有一个 char*s（声明为）char** 数组，其中该数组是动态分配的（通过 calloc），但其中的 char*s 是静态的。

这对我来说很好，直到我尝试释放数组（在调整大小期间），此时我得到

*** glibc detected *** ./hash_table_test: free(): invalid next size (normal): 0x0891f028 ***

我尝试将数组中的所有 ptrs 设置为 NULL，但随后出现错误

*** glibc detected *** ./hash_table_test: double free or corruption (!prev): 0x0815b028 ***

以下是相关代码：

表结构：

struct string_hash_table {

//Array of c-strings
char** table;
//number of elements in the table
int num_elements;
//size of table
int table_size;

//Primes
int *primes;
//Current position in primes array
int primes_index;
//the size of the primes array
int primes_size;
};
//TypeDefs--------------------------------
typedef struct string_hash_table HashTable;

Rehash 函数（错误来源）

void rehash_string(HashTable *table) {

int prev_size = table->table_size;
int i;

table->table_size = table->table_size * 2;

//create new array
char** new_table = calloc(table->table_size, sizeof(char*));
printf("new table created\n");
int index;
printf("before loop prev_size is %d\n", prev_size);
//add all elements to new_table
for (i = 0; i < prev_size; i++) {
    printf("on %d\n", i);
    index = find_spot_string(new_table, table->table_size, table->table[i]);
    printf("after find_spot_string\n");
    if (index != -1) {
        table->table[index] = table->table[i];
    }
}

//free and swap
printf("before free\n");
empty_string_array(table->table, table->table_size);
free(table->table);
table->table = new_table;

HashTable 结构的初始化：

//Takes a HashTable and initializes it
void init_hash_table(HashTable *table) {

table->primes_index = 0;
table->num_elements = 0;
table->primes_size = 297;
table->primes = prime_list;

table->table_size = table->primes[0];
table->table = calloc(table->table_size, sizeof(char*));
}

静态字符串的声明：

    char* temp = "hello";
add_hash_table_string(table, temp);

temp = "luck";
add_hash_table_string(table, temp);

temp = "stuck";
add_hash_table_string(table, temp);

temp = "buck";
add_hash_table_string(table, temp);

temp = "muck";
add_hash_table_string(table, temp);

temp = "much";
add_hash_table_string(table, temp);

目前我只是在这里测试我的代码，除了上面的重新散列函数外，一切正常。有人有想法么？还是我应该遵循的线索？

编辑：为 add_hash_table_string 添加代码

void add_hash_table_string(HashTable *table, char* element) {

    //if non-null element, and element is not in the HashTable
    if (element != NULL && contains_hash_table_string(table, element) == 1) {

        //if the table is full
        if (table->table_size / 2 < table->num_elements) {

            rehash_string(table);
        }

        int index = find_spot_string(table->table, table->table_size, element);

        table->table[index] = element;
        table->num_elements++;
    }
}

编辑2：

忘记准确了，错误发生在 rehash 函数中的 free(table->table) 行

4

1 回答 1

3

一个可能的问题是，您使用新大小释放旧表

empty_string_array(table->table, table->table_size);

另一个可能是

index = find_spot_string(new_table, table->table_size, table->table[i]);
printf("after find_spot_string\n");
if (index != -1) {
    table->table[index] = table->table[i];

如果这应该将条目复制到new_table，则它不是 AFAICS。当index大于时prev_size，你写超出结尾table。

于 2012-12-02T21:21:10.780 回答