因此,我是C语言的新手,我正在为一个普通的位图图像识别程序编写一个矩阵压缩函数。我有以下代码,Valgrind告诉我以下标记行有内存泄漏,尽管我不知道是什么原因造成的。任何意见,将不胜感激。
/* Returns a NULL-terminated list of Row structs, each containing a NULL-terminated list of Elem structs.
* See sparsify.h for descriptions of the Row/Elem structs.
* Each Elem corresponds to an entry in dense_matrix whose value is not 255 (white).
* This function can return NULL if the dense_matrix is entirely white.
*/
Row *dense_to_sparse(unsigned char *dense_matrix, int width, int height) {
Row *result = NULL;
_Bool first_row;
for (int row = height - 1; row >= 0; row--) {
first_row = 0;
for (int elem = width - 1; elem >= 0; elem--) {
unsigned char curr_item = dense_matrix[(row*width) + elem];
if (curr_item!= 255) {
if (!first_row) {
(Memory Leak) Row *curr_row = (Row *) malloc(sizeof(Row));
if (curr_row == NULL) {
allocation_failed();
}
curr_row->next = result;
curr_row->y = row;
curr_row->elems = NULL;
result = curr_row;
//free(curr_row);
first_row = 1;
}
(Memory Leak) Elem *curr_elem = (Elem *) malloc(sizeof(Elem));
if (curr_elem == NULL) {
allocation_failed();
}
curr_elem->value = curr_item;
curr_elem->x = elem;
curr_elem->next = result->elems;
result->elems = curr_elem;
//free(curr_elem);
}
}
}
return result;
}
我相信释放curr_row和curr_elem可能是一个问题,尽管当我尝试在每个循环结束时释放它们时,它给了我运行时错误:
parsify(73897,0x7fff75584310)malloc:*对象0x7fbf81403a48错误:释放的对象的校验和不正确-释放后可能已修改了对象。
您不能free
在其中进行存储,dense_to_sparse
因为该功能的全部目的是创建并返回新分配的数据结构。大概,调用的代码dense_to_sparse
想要使用结果。
您将需要一个单独的函数来释放不再需要时应调用的内存。
void free_sparse_matrix (Row *matrix)
{
Row *row = matrix;
while (row != NULL) {
Row *next_row = row->next;
Elem *elem = row->elems;
while (elem != NULL) {
Elem *next_elem = elem->next;
free (elem);
elem = next_elem;
}
free (row);
row = next_row;
}
}
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