I've been having this problem while trying to create a generic Priority Queue.
Valgrind gives me these errors :
HEAP SUMMARY:
==39639== in use at exit: 0 bytes in 0 blocks
==39639== total heap usage: 22 allocs, 22 frees, 1,811 bytes allocated
==39639==
==39639== All heap blocks were freed -- no leaks are possible
==39639==
==39639== ERROR SUMMARY: 4 errors from 2 contexts (suppressed: 6 from 6)
==39639==
==39639== 2 errors in context 1 of 2:
==39639== Invalid read of size 8
==39639== at 0x405FB5: mtm::PriorityQueue<int, Assignment>::Iterator::operator++() (priority_queue.h:505)
==39639== by 0x405D2E: mtm::PriorityQueue<int, Assignment>::erase(mtm::PriorityQueue<int, Assignment>::Iterator, mtm::PriorityQueue<int, Assignment>::Iterator) (priority_queue.h:808)
==39639== by 0x403BC0: eraseAndSizeTest() (priority_queue_test.cpp:119)
==39639== by 0x404D6B: main (priority_queue_test.cpp:136)
==39639== Address 0x5141c88 is 24 bytes inside a block of size 32 free'd
==39639== at 0x4A05FD6: operator delete(void*) (vg_replace_malloc.c:480)
==39639== by 0x405B1B: mtm::PriorityQueue<int, Assignment>::erase(mtm::PriorityQueue<int, Assignment>::Iterator) (priority_queue.h:768)
==39639== by 0x405D04: mtm::PriorityQueue<int, Assignment>::erase(mtm::PriorityQueue<int, Assignment>::Iterator, mtm::PriorityQueue<int, Assignment>::Iterator) (priority_queue.h:809)
==39639== by 0x403BC0: eraseAndSizeTest() (priority_queue_test.cpp:119)
==39639== by 0x404D6B: main (priority_queue_test.cpp:136)
==39639==
==39639==
==39639== 2 errors in context 2 of 2:
==39639== Invalid read of size 8
==39639== at 0x4CCB870: std::string::size() const (basic_string.h:713)
==39639== by 0x4050E8: __gnu_cxx::__enable_if<std::__is_char<char>::__value, bool>::__type std::operator==<char>(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (in /u1/115/saoren/mtm/HW5/wet5/prog)
==39639== by 0x405048: Assignment::operator==(Assignment const&) const (priority_queue_test.cpp:26)
==39639== by 0x406337: mtm::PriorityQueue<int, Assignment>::Iterator::operator==(mtm::PriorityQueue<int, Assignment>::Iterator const&) const (priority_queue.h:553)
==39639== by 0x406010: mtm::PriorityQueue<int, Assignment>::Iterator::operator=(mtm::PriorityQueue<int, Assignment>::Iterator const&) (priority_queue.h:451)
==39639== by 0x405D1B: mtm::PriorityQueue<int, Assignment>::erase(mtm::PriorityQueue<int, Assignment>::Iterator, mtm::PriorityQueue<int, Assignment>::Iterator) (priority_queue.h:809)
==39639== by 0x403BC0: eraseAndSizeTest() (priority_queue_test.cpp:119)
==39639== by 0x404D6B: main (priority_queue_test.cpp:136)
==39639== Address 0x5141c70 is 0 bytes inside a block of size 32 free'd
==39639== at 0x4A05FD6: operator delete(void*) (vg_replace_malloc.c:480)
==39639== by 0x405B1B: mtm::PriorityQueue<int, Assignment>::erase(mtm::PriorityQueue<int, Assignment>::Iterator) (priority_queue.h:768)
==39639== by 0x405D04: mtm::PriorityQueue<int, Assignment>::erase(mtm::PriorityQueue<int, Assignment>::Iterator, mtm::PriorityQueue<int, Assignment>::Iterator) (priority_queue.h:809)
==39639== by 0x403BC0: eraseAndSizeTest() (priority_queue_test.cpp:119)
==39639== by 0x404D6B: main (priority_queue_test.cpp:136)
==39639==
--39639--
--39639-- used_suppression: 4 U1004-ARM-_dl_relocate_object
--39639-- used_suppression: 2 glibc-2.5.x-on-SUSE-10.2-(PPC)-2a
==39639==
==39639== ERROR SUMMARY: 4 errors from 2 contexts (suppressed: 6 from 6)
and here is my code (relevent parts, I believe) :
template<typename Priority, typename T>
typename PriorityQueue<Priority, T>::Iterator PriorityQueue<Priority, T>::Iterator::operator+(
int offset) {
if (offset == 0) {
return *this;
}
Iterator it = *this;
for (int i = 0; i < offset; i++) {
it++;
}
//TODO: SHOULD WE ALLOCATE NEWITERATOR WITH NEW ??
return it;
}`
`template<typename Priority, typename T>
typename PriorityQueue<Priority, T>::Iterator PriorityQueue<Priority, T>::Iterator::operator++() {
//TODO: CHECK IF NOT NULL
if (this->data != nullptr) {
data = data->next;
index++;
}
return *this;
}
template<typename Priority, typename T>
typename PriorityQueue<Priority, T>::Iterator PriorityQueue<Priority, T>::Iterator::operator++(
int) {
Iterator it = *this;
if (this->data != nullptr) {
if (this->data->next == nullptr) {
data = nullptr;
index++;
return *this;
}
data = data->next;
index++;
}
return it;
}
template<typename Priority, typename T>
typename PriorityQueue<Priority, T>::Iterator PriorityQueue<Priority, T>::erase(
Iterator exactPosition) {
if (elementsNo == 0) {
return end();
}
bool lastOne = false;
bool firstOne = false;
lastOne = exactPosition + 1 == end();
firstOne = exactPosition == begin();
if (firstOne) {
elementsNo--;
head = head->next;
delete (exactPosition.data);
exactPosition.data = nullptr;
return begin();
}
Iterator previousPosition = begin();
while (previousPosition.data->next != exactPosition.data) {
previousPosition++;
}
if (lastOne) {
elementsNo--;
delete exactPosition.data;
previousPosition.data->next = nullptr;
return end();
}
Node* next = exactPosition.data->next;
previousPosition.data->next = next;
delete exactPosition.data;
exactPosition.data = nullptr;
this->elementsNo--;
return Iterator(next, exactPosition.index + 1);
}
template<typename Priority, typename T>
typename PriorityQueue<Priority, T>::Iterator PriorityQueue<Priority, T>::erase(
Iterator start, Iterator end) {
if (!size()) {
return end;
}
//TODO: CHECK BOUNDRIES (START AFTER END)
Iterator iterator = start;
//FOREACH(iterator,start,end)
for (Iterator i = start; i != end; ++i) {
iterator = erase(iterator);
}
return ++iterator;
template<typename Priority, typename T>
bool PriorityQueue<Priority, T>::Iterator::operator==(
const Iterator& original) const {
if (data == nullptr && original.data == nullptr) {
return true;
}
if (data == nullptr || original.data == nullptr) {
return false;
}
return data->element.data == original.data->element.data;
}
I would really appreciate it if someone could spot the faults and let me know even though there a lot of functions and a lot of errors it's all goes down to erase.
