// Copyright (c) 2014, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.

#pragma once
#ifndef ROCKSDB_LITE

#include <string>
#include "rocksdb/table.h"
#include "util/murmurhash.h"
#include "rocksdb/options.h"

namespace rocksdb {

const uint32_t kCuckooMurmurSeedMultiplier = 816922183;
static inline uint64_t CuckooHash(
    const Slice& user_key, uint32_t hash_cnt, bool use_module_hash,
    uint64_t table_size_, bool identity_as_first_hash,
    uint64_t (*get_slice_hash)(const Slice&, uint32_t, uint64_t)) {

#if !defined NDEBUG || defined OS_WIN
  // This part is used only in unit tests but we have to keep it for Windows build as we run test in both debug and release modes under Windows.
  if (get_slice_hash != nullptr) {
    return get_slice_hash(user_key, hash_cnt, table_size_);
  }
#endif

  uint64_t value = 0;
  if (hash_cnt == 0 && identity_as_first_hash) {
    value = (*reinterpret_cast<const int64_t*>(user_key.data()));
  } else {
    value = MurmurHash(user_key.data(), static_cast<int>(user_key.size()),
                       kCuckooMurmurSeedMultiplier * hash_cnt);
  }
  if (use_module_hash) {
    return value % table_size_;
  } else {
    return value & (table_size_ - 1);
  }
}

// Cuckoo Table is designed for applications that require fast point lookups
// but not fast range scans.
//
// Some assumptions:
// - Key length and Value length are fixed.
// - Does not support Snapshot.
// - Does not support Merge operations.
class CuckooTableFactory : public TableFactory {
 public:
  explicit CuckooTableFactory(const CuckooTableOptions& table_options)
    : table_options_(table_options) {}
  ~CuckooTableFactory() {}

  const char* Name() const override { return "CuckooTable"; }

  Status NewTableReader(
      const ImmutableCFOptions& ioptions, const EnvOptions& env_options,
      const InternalKeyComparator& internal_comparator,
      unique_ptr<RandomAccessFile>&& file, uint64_t file_size,
      unique_ptr<TableReader>* table) const override;

  TableBuilder* NewTableBuilder(
      const TableBuilderOptions& table_builder_options,
      WritableFile* file) const override;

  // Sanitizes the specified DB Options.
  Status SanitizeOptions(const DBOptions& db_opts,
                         const ColumnFamilyOptions& cf_opts) const override {
    return Status::OK();
  }

  std::string GetPrintableTableOptions() const override;

 private:
  const CuckooTableOptions table_options_;
};

}  // namespace rocksdb
#endif  // ROCKSDB_LITE