leveldb::anonymous_namespace{cache.cc}::HandleTable Class Reference

Collaboration diagram for leveldb::anonymous_namespace{cache.cc}::HandleTable:

Public Member Functions
	HandleTable ()
	~HandleTable ()
LRUHandle *	Lookup (const Slice &key, uint32_t hash)
LRUHandle *	Insert (LRUHandle *h)
LRUHandle *	Remove (const Slice &key, uint32_t hash)

Private Member Functions
LRUHandle **	FindPointer (const Slice &key, uint32_t hash)
void	Resize ()

Private Attributes
uint32_t	length_
uint32_t	elems_
LRUHandle **	list_

Detailed Description

Definition at line 71 of file cache.cc.

Constructor & Destructor Documentation

HandleTable()

leveldb::anonymous_namespace{cache.cc}::HandleTable::HandleTable ( )

inline

Definition at line 73 of file cache.cc.

: length_(0), elems_(0), list_(NULL) { Resize(); }

~HandleTable()

leveldb::anonymous_namespace{cache.cc}::HandleTable::~HandleTable ( )

inline

Definition at line 74 of file cache.cc.

{ delete[] list_; }

Member Function Documentation

FindPointer()

LRUHandle** leveldb::anonymous_namespace{cache.cc}::HandleTable::FindPointer ( const Slice &  key, uint32_t  hash  )

inlineprivate

Definition at line 116 of file cache.cc.

                                                           {
    LRUHandle** ptr = &list_[hash & (length_ - 1)];
    while (*ptr != NULL &&
           ((*ptr)->hash != hash || key != (*ptr)->key())) {
      ptr = &(*ptr)->next_hash;
    }
    return ptr;
  }

Insert()

LRUHandle* leveldb::anonymous_namespace{cache.cc}::HandleTable::Insert ( LRUHandle *  h )

inline

Definition at line 80 of file cache.cc.

                                  {
    LRUHandle** ptr = FindPointer(h->key(), h->hash);
    LRUHandle* old = *ptr;
    h->next_hash = (old == NULL ? NULL : old->next_hash);
    *ptr = h;
    if (old == NULL) {
      ++elems_;
      if (elems_ > length_) {
        // Since each cache entry is fairly large, we aim for a small
        // average linked list length (<= 1).
        Resize();
      }
    }
    return old;
  }

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Lookup()

LRUHandle* leveldb::anonymous_namespace{cache.cc}::HandleTable::Lookup ( const Slice &  key, uint32_t  hash  )

inline

Definition at line 76 of file cache.cc.

                                                     {
    return *FindPointer(key, hash);
  }

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Remove()

LRUHandle* leveldb::anonymous_namespace{cache.cc}::HandleTable::Remove ( const Slice &  key, uint32_t  hash  )

inline

Definition at line 96 of file cache.cc.

                                                     {
    LRUHandle** ptr = FindPointer(key, hash);
    LRUHandle* result = *ptr;
    if (result != NULL) {
      *ptr = result->next_hash;
      --elems_;
    }
    return result;
  }

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Resize()

void leveldb::anonymous_namespace{cache.cc}::HandleTable::Resize ( )

inlineprivate

Definition at line 125 of file cache.cc.

                {
    uint32_t new_length = 4;
    while (new_length < elems_) {
      new_length *= 2;
    }
    LRUHandle** new_list = new LRUHandle*[new_length];
    memset(new_list, 0, sizeof(new_list[0]) * new_length);
    uint32_t count = 0;
    for (uint32_t i = 0; i < length_; i++) {
      LRUHandle* h = list_[i];
      while (h != NULL) {
        LRUHandle* next = h->next_hash;
        uint32_t hash = h->hash;
        LRUHandle** ptr = &new_list[hash & (new_length - 1)];
        h->next_hash = *ptr;
        *ptr = h;
        h = next;
        count++;
      }
    }
    assert(elems_ == count);
    delete[] list_;
    list_ = new_list;
    length_ = new_length;
  }

Member Data Documentation

elems_

uint32_t leveldb::anonymous_namespace{cache.cc}::HandleTable::elems_

private

Definition at line 110 of file cache.cc.

length_

uint32_t leveldb::anonymous_namespace{cache.cc}::HandleTable::length_

private

Definition at line 109 of file cache.cc.

list_

LRUHandle** leveldb::anonymous_namespace{cache.cc}::HandleTable::list_

private

Definition at line 111 of file cache.cc.

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

• util/cache.cc