blender
/
blender
136
406
Fork 589
Code Issues 6.3k Pull Requests 766 Projects 19 Wiki Activity

BLI: add Map.pop_try method 

I found this pattern in depsgraph code more than once.
This commit is contained in:
Jacques Lucke 2020-06-10 14:47:16 +02:00
parent 75ce20a000
commit a71f073dfb
2 changed files with 51 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
source/blender/blenlib/BLI_map.hh
View File

@ -73,6 +73,7 @@
#include "BLI_hash.hh"
#include "BLI_hash_tables.hh"
#include "BLI_map_slots.hh"
#include "BLI_optional.hh"
#include "BLI_probing_strategies.hh"
namespace blender {
@ -387,6 +388,23 @@ class Map {
return this->pop__impl(key, m_hash(key));
}
/**
* Get the value that is stored for the given key and remove it from the map. If the key is not
* in the map, a value-less optional is returned.
*/
Optional<Value> pop_try(const Key &key)
{
return this->pop_try_as(key);
}
/**
* Same as `pop_try`, but accepts other key types that are supported by the hash function.
*/
template<typename ForwardKey> Optional<Value> pop_try_as(const ForwardKey &key)
{
return this->pop_try__impl(key, m_hash(key));
}
/**
* This method can be used to implement more complex custom behavior without having to do
* multiple lookups
@ -1029,6 +1047,22 @@ class Map {
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey> Optional<Value> pop_try__impl(const ForwardKey &key, uint32_t hash)
{
MAP_SLOT_PROBING_BEGIN (hash, slot) {
if (slot.contains(key, m_is_equal, hash)) {
Optional<Value> value = *slot.value();
slot.remove();
m_removed_slots++;
return value;
}
if (slot.is_empty()) {
return {};
}
}
MAP_SLOT_PROBING_END();
}
template<typename ForwardKey, typename CreateValueF, typename ModifyValueF>
auto add_or_modify__impl(ForwardKey &&key,
const CreateValueF &create_value,

17
tests/gtests/blenlib/BLI_map_test.cc
View File

@ -82,6 +82,23 @@ TEST(map, PopItem)
EXPECT_FALSE(map.contains(1));
}
TEST(map, PopTry)
{
Map<int, int> map;
map.add(1, 5);
map.add(2, 7);
EXPECT_EQ(map.size(), 2);
Optional<int> value = map.pop_try(4);
EXPECT_EQ(map.size(), 2);
EXPECT_FALSE(value.has_value());
value = map.pop_try(2);
EXPECT_EQ(map.size(), 1);
EXPECT_TRUE(value.has_value());
EXPECT_EQ(value.value(), 7);
EXPECT_EQ(*map.pop_try(1), 5);
EXPECT_EQ(map.size(), 0);
}
TEST(map, PopItemMany)
{
Map<int, int> map;