mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-26 23:29:22 +00:00
ADT: Fix MapVector::erase()
Actually update the changed indexes in the map portion of `MapVector` when erasing from the middle. Add a unit test that checks for this. Note that `MapVector::erase()` is a linear time operation (it was and still is). I'll commit a new method in a moment called `MapVector::remove_if()` that deletes multiple entries in linear time, which should be slightly less painful. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213084 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
9f865ed141
commit
d9ebc5991b
@ -1442,7 +1442,7 @@ iteration over maps of pointers.
|
||||
|
||||
It is implemented by mapping from key to an index in a vector of key,value
|
||||
pairs. This provides fast lookup and iteration, but has two main drawbacks: The
|
||||
key is stored twice and it doesn't support removing elements.
|
||||
key is stored twice and removing elements takes linear time.
|
||||
|
||||
.. _dss_inteqclasses:
|
||||
|
||||
|
@ -125,12 +125,26 @@ public:
|
||||
}
|
||||
|
||||
/// \brief Remove the element given by Iterator.
|
||||
///
|
||||
/// Returns an iterator to the element following the one which was removed,
|
||||
/// which may be end().
|
||||
///
|
||||
/// \note This is a deceivingly expensive operation (linear time). It's
|
||||
/// usually better to use \a remove_if() if possible.
|
||||
typename VectorType::iterator erase(typename VectorType::iterator Iterator) {
|
||||
typename MapType::iterator MapIterator = Map.find(Iterator->first);
|
||||
Map.erase(MapIterator);
|
||||
return Vector.erase(Iterator);
|
||||
Map.erase(Iterator->first);
|
||||
auto Next = Vector.erase(Iterator);
|
||||
if (Next == Vector.end())
|
||||
return Next;
|
||||
|
||||
// Update indices in the map.
|
||||
size_t Index = Next - Vector.begin();
|
||||
for (auto &I : Map) {
|
||||
assert(I.second != Index && "Index was already erased!");
|
||||
if (I.second > Index)
|
||||
--I.second;
|
||||
}
|
||||
return Next;
|
||||
}
|
||||
};
|
||||
|
||||
|
@ -53,3 +53,18 @@ TEST(MapVectorTest, insert_pop) {
|
||||
EXPECT_EQ(MV[1], 2);
|
||||
EXPECT_EQ(MV[4], 7);
|
||||
}
|
||||
|
||||
TEST(MapVectorTest, erase) {
|
||||
MapVector<int, int> MV;
|
||||
|
||||
MV.insert(std::make_pair(1, 2));
|
||||
MV.insert(std::make_pair(3, 4));
|
||||
MV.insert(std::make_pair(5, 6));
|
||||
ASSERT_EQ(MV.size(), 3u);
|
||||
|
||||
MV.erase(MV.find(1));
|
||||
ASSERT_EQ(MV.size(), 2u);
|
||||
ASSERT_EQ(MV.find(1), MV.end());
|
||||
ASSERT_EQ(MV[3], 4);
|
||||
ASSERT_EQ(MV[5], 6);
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user