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Diffstat (limited to 'src/leveldb/db/memtable.cc')
-rw-r--r-- | src/leveldb/db/memtable.cc | 145 |
1 files changed, 0 insertions, 145 deletions
diff --git a/src/leveldb/db/memtable.cc b/src/leveldb/db/memtable.cc deleted file mode 100644 index bfec0a7e7..000000000 --- a/src/leveldb/db/memtable.cc +++ /dev/null @@ -1,145 +0,0 @@ -// Copyright (c) 2011 The LevelDB Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. See the AUTHORS file for names of contributors. - -#include "db/memtable.h" -#include "db/dbformat.h" -#include "leveldb/comparator.h" -#include "leveldb/env.h" -#include "leveldb/iterator.h" -#include "util/coding.h" - -namespace leveldb { - -static Slice GetLengthPrefixedSlice(const char* data) { - uint32_t len; - const char* p = data; - p = GetVarint32Ptr(p, p + 5, &len); // +5: we assume "p" is not corrupted - return Slice(p, len); -} - -MemTable::MemTable(const InternalKeyComparator& cmp) - : comparator_(cmp), - refs_(0), - table_(comparator_, &arena_) { -} - -MemTable::~MemTable() { - assert(refs_ == 0); -} - -size_t MemTable::ApproximateMemoryUsage() { return arena_.MemoryUsage(); } - -int MemTable::KeyComparator::operator()(const char* aptr, const char* bptr) - const { - // Internal keys are encoded as length-prefixed strings. - Slice a = GetLengthPrefixedSlice(aptr); - Slice b = GetLengthPrefixedSlice(bptr); - return comparator.Compare(a, b); -} - -// Encode a suitable internal key target for "target" and return it. -// Uses *scratch as scratch space, and the returned pointer will point -// into this scratch space. -static const char* EncodeKey(std::string* scratch, const Slice& target) { - scratch->clear(); - PutVarint32(scratch, target.size()); - scratch->append(target.data(), target.size()); - return scratch->data(); -} - -class MemTableIterator: public Iterator { - public: - explicit MemTableIterator(MemTable::Table* table) : iter_(table) { } - - virtual bool Valid() const { return iter_.Valid(); } - virtual void Seek(const Slice& k) { iter_.Seek(EncodeKey(&tmp_, k)); } - virtual void SeekToFirst() { iter_.SeekToFirst(); } - virtual void SeekToLast() { iter_.SeekToLast(); } - virtual void Next() { iter_.Next(); } - virtual void Prev() { iter_.Prev(); } - virtual Slice key() const { return GetLengthPrefixedSlice(iter_.key()); } - virtual Slice value() const { - Slice key_slice = GetLengthPrefixedSlice(iter_.key()); - return GetLengthPrefixedSlice(key_slice.data() + key_slice.size()); - } - - virtual Status status() const { return Status::OK(); } - - private: - MemTable::Table::Iterator iter_; - std::string tmp_; // For passing to EncodeKey - - // No copying allowed - MemTableIterator(const MemTableIterator&); - void operator=(const MemTableIterator&); -}; - -Iterator* MemTable::NewIterator() { - return new MemTableIterator(&table_); -} - -void MemTable::Add(SequenceNumber s, ValueType type, - const Slice& key, - const Slice& value) { - // Format of an entry is concatenation of: - // key_size : varint32 of internal_key.size() - // key bytes : char[internal_key.size()] - // value_size : varint32 of value.size() - // value bytes : char[value.size()] - size_t key_size = key.size(); - size_t val_size = value.size(); - size_t internal_key_size = key_size + 8; - const size_t encoded_len = - VarintLength(internal_key_size) + internal_key_size + - VarintLength(val_size) + val_size; - char* buf = arena_.Allocate(encoded_len); - char* p = EncodeVarint32(buf, internal_key_size); - memcpy(p, key.data(), key_size); - p += key_size; - EncodeFixed64(p, (s << 8) | type); - p += 8; - p = EncodeVarint32(p, val_size); - memcpy(p, value.data(), val_size); - assert((p + val_size) - buf == encoded_len); - table_.Insert(buf); -} - -bool MemTable::Get(const LookupKey& key, std::string* value, Status* s) { - Slice memkey = key.memtable_key(); - Table::Iterator iter(&table_); - iter.Seek(memkey.data()); - if (iter.Valid()) { - // entry format is: - // klength varint32 - // userkey char[klength] - // tag uint64 - // vlength varint32 - // value char[vlength] - // Check that it belongs to same user key. We do not check the - // sequence number since the Seek() call above should have skipped - // all entries with overly large sequence numbers. - const char* entry = iter.key(); - uint32_t key_length; - const char* key_ptr = GetVarint32Ptr(entry, entry+5, &key_length); - if (comparator_.comparator.user_comparator()->Compare( - Slice(key_ptr, key_length - 8), - key.user_key()) == 0) { - // Correct user key - const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8); - switch (static_cast<ValueType>(tag & 0xff)) { - case kTypeValue: { - Slice v = GetLengthPrefixedSlice(key_ptr + key_length); - value->assign(v.data(), v.size()); - return true; - } - case kTypeDeletion: - *s = Status::NotFound(Slice()); - return true; - } - } - } - return false; -} - -} // namespace leveldb |