duckdb::Node256 Class Reference

Node256 holds up to 256 children. They are indexed by their key byte. More...

Collaboration diagram for duckdb::Node256:

Public Member Functions
	Node256 (const Node256 &)=delete
Node256 &	operator= (const Node256 &)=delete
void	ReplaceChild (const uint8_t byte, const Node child)
	Replace the child at byte.
NodeChildren	ExtractChildren (ArenaAllocator &arena)

Static Public Member Functions
static NodeHandle< Node256 >	New (ART &art, Node &node)
	Get a new Node256 handle and initialize the Node256.
static void	InsertChild (ART &art, Node &node, const uint8_t byte, const Node child)
	Insert a child at byte.
static void	DeleteChild (ART &art, Node &node, const uint8_t byte)
	Delete the child at byte.
template<class F , class NODE >
static void	Iterator (NODE &n, F &&lambda)
template<class NODE >
static unsafe_optional_ptr< Node >	GetChild (NODE &n, const uint8_t byte, const bool unsafe=false)
template<class NODE >
static unsafe_optional_ptr< Node >	GetNextChild (NODE &n, uint8_t &byte)

Static Public Attributes
static constexpr NType	NODE_256 = NType::NODE_256
static constexpr uint16_t	CAPACITY = 256
static constexpr uint8_t	SHRINK_THRESHOLD = 36

Static Private Member Functions
static void	GrowNode48 (ART &art, Node &node256, Node &node48)

Private Attributes
uint16_t	count
Node	children [CAPACITY]

Friends
class	Node48

Detailed Description

Node256 holds up to 256 children. They are indexed by their key byte.

Member Function Documentation

New()

static NodeHandle< Node256 > duckdb::Node256::New ( ART &  art, Node &  node  )

inlinestatic

Get a new Node256 handle and initialize the Node256.

                                                         {
        node = Node::GetAllocator(art, NODE_256).New();
        node.SetMetadata(static_cast<uint8_t>(NODE_256));
 
        NodeHandle<Node256> handle(art, node);
        auto &n = handle.Get();
 
        // Reset the node (count and children).
        n.count = 0;
        for (uint16_t i = 0; i < CAPACITY; i++) {
            n.children[i].Clear();
        }
 
        return handle;
    }

Here is the call graph for this function:

ReplaceChild()

void duckdb::Node256::ReplaceChild ( const uint8_t  byte, const Node  child  )

inline

Replace the child at byte.

                                                            {
        D_ASSERT(count > SHRINK_THRESHOLD);
        auto status = children[byte].GetGateStatus();
        children[byte] = child;
        if (status == GateStatus::GATE_SET && child.HasMetadata()) {
            children[byte].SetGateStatus(status);
        }
    }

Here is the call graph for this function:

Iterator()

template<class F , class NODE >

static void duckdb::Node256::Iterator ( NODE &  n, F &&  lambda  )

inlinestatic

                                              {
        D_ASSERT(n.count);
        for (idx_t i = 0; i < CAPACITY; i++) {
            if (n.children[i].HasMetadata()) {
                lambda(n.children[i]);
            }
        }
    }

GetChild()

template<class NODE >

static unsafe_optional_ptr< Node > duckdb::Node256::GetChild ( NODE &  n, const uint8_t  byte, const bool  unsafe = false  )

inlinestatic

                                                                                                      {
        if (unsafe) {
            return &n.children[byte];
        }
        if (n.children[byte].HasMetadata()) {
            return &n.children[byte];
        }
        return nullptr;
    }

GetNextChild()

template<class NODE >

static unsafe_optional_ptr< Node > duckdb::Node256::GetNextChild ( NODE &  n, uint8_t &  byte  )

inlinestatic

                                                                          {
        for (idx_t i = byte; i < CAPACITY; i++) {
            if (n.children[i].HasMetadata()) {
                byte = UnsafeNumericCast<uint8_t>(i);
                return &n.children[i];
            }
        }
        return nullptr;
    }

ExtractChildren()

NodeChildren duckdb::Node256::ExtractChildren ( ArenaAllocator &  arena )

inline

Extracts the bytes and their respective children. The return value is valid as long as the arena is valid. The node must be freed after calling into this function.

                                                        {
        auto mem_bytes = arena.AllocateAligned(sizeof(uint8_t) * count);
        array_ptr<uint8_t> bytes(mem_bytes, count);
        auto mem_children = arena.AllocateAligned(sizeof(Node) * count);
        array_ptr<Node> children_ptr(reinterpret_cast<Node *>(mem_children), count);
 
        uint16_t ptr_idx = 0;
        for (idx_t i = 0; i < CAPACITY; i++) {
            if (children[i].HasMetadata()) {
                bytes[ptr_idx] = UnsafeNumericCast<uint8_t>(i);
                children_ptr[ptr_idx] = children[i];
                ptr_idx++;
            }
        }
 
        return NodeChildren(bytes, children_ptr);
    }

---

The documentation for this class was generated from the following file:

• external/duckdb/duckdb.cpp