在VS2008中用C++生成DLL为Test，Test中有类BM，BM定义如下：如何在C#中调用BM中的insert和contains成员函数调用？
  class BM
  {
public:
bloom_filter(unsigned int tbl_size)
{
table_size = tbl_size;
hash_table = new unsigned char[table_size];
for(std::size_t i = 0; i < table_size; ++i) hash_table[i] = 0;
}

void insert(char* key)
{
for(std::size_t i = 0; i < hash_function.size(); i++)
{
unsigned int hash = hash_function[i](key,3) % (table_size * char_size);
hash_table[hash / char_size] |= bit_mask[hash % char_size];
}
}
/* bool contains(const std::string& key)*/
bool contains(char* key)
{
for(std::size_t i = 0; i < hash_function.size(); i++)
{
unsigned int hash = hash_function[i](key,3) % (table_size * char_size);
unsigned int bit = hash % char_size;
if ((hash_table[hash / char_size] & bit_mask[bit]) != bit_mask[bit])
{
return false;
}
}
return true;
}

private:
std::vector < hash_function > hash_function;
unsigned char* hash_table;
unsigned int table_size;
};