A question about the find function of Google dense_hash_map - c++

Question

I use Google’s dense_hash_map as a cache of some data. When I use the find function to find a key, I find that it doesn’t exist, but when traversing dense_hash_map, I can see that the key exists. Is it wrong where I used it? By the way, I have rewritten the EqualKey class required by dense_hash_map.
This is my test code:
class StringVal {
public:
StringVal(string &str) {
len = str.length();
ptr = new uint8_t[len];
memcpy(ptr, str.c_str(), len);
}
StringVal(uint8_t* ptr = NULL, int len = 0) : len(len), ptr(ptr) {
if(ptr == NULL) {
is_null = NULL;
}
}
StringVal(const char* ptr) : len(strlen(ptr)),ptr(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(ptr))) {
if(ptr == NULL) {
is_null = NULL;
}
}
~StringVal() {
delete[] ptr;
}
uint8_t* ptr;
int len;
bool is_null;
static StringVal null() {
StringVal sv;
sv.is_null = true;
return sv;
}
bool operator==(const StringVal& other) const {
if (is_null != other.is_null) return false;
if (is_null) return true;
if (len != other.len) return false;
return ptr == other.ptr || memcmp(ptr, other.ptr, len) == 0;
}
bool operator!=(const StringVal& other) const { return !(*this == other); }
};
struct NewStringValCmp {
bool operator()(const StringVal* s1, const StringVal* s2) const {
if (s1 == NULL && s2 == NULL) return 1;
if (s1 == NULL || s2 == NULL) return 0;
if (s1->is_null != s2->is_null) return false;
if (s1->is_null) return true;
if (s1->len != s2->len) return false;
return memcmp(s1->ptr, s2->ptr, s1->len) == 0;
}
};
typedef dense_hash_map<StringVal*, StringVal*, std::hash<StringVal*>, NewStringValCmp> new_dict_map_string_t;
vector<string> data = {
"test1","1",
"test2","2",
"test3","3",
"test4","4",
"test5","5",
"test6","6",
"test7","7",
"test8","8",
"test9","9",
"test10","10"
};
int main() {
new_dict_map_string_t* cm = new new_dict_map_string_t();
cm->set_empty_key(NULL);
for (int i = 0; (i + 1) < data.size(); i+=2) {
StringVal *key = new StringVal(data[i]);
StringVal *value = new StringVal(data[i+1]);
(*cm)[key] = value;
}
string input = "";
while (1) {
cin >> input;
if (input == "q") {
break;
}
StringVal *target = new StringVal(input);
for (auto itor: *cm) {
if (*(itor.first) == *target) {
cout << "find target" << endl;
}
}
auto itor = cm->find(target);
if (itor == cm->end()) {
cout << "cm->find nothing" << endl;
} else {
cout << itor->second->ptr << endl;
}
delete target;
input = "";
}
for (auto iter : *cm) {
delete iter.first;
delete iter.second;
}
delete cm;
return 0;
}