//

// RocksDBBlockBasedTableOptions.h

// ObjectiveRocks

//

// Created by Iska on 02/01/15.

// Copyright (c) 2015 BrainCookie. All rights reserved.

//

#import <Foundation/Foundation.h>

#import "RocksDBCache.h"

#import "RocksDBFilterPolicy.h"

NS_ASSUME_NONNULL_BEGIN

typedef NS_ENUM(char, BlockBasedTableIndexType)

{

/**

@brief A space efficient index block that is optimized for

binary-search-based index.

*/

BlockBasedTableIndexBinarySearch,

/**

@brief The hash index, if enabled, will do the hash lookup when

a prefix extractor is provided.

@see RocksDBPrefixExtractor

*/

BlockBasedTableIndexHashSearch

};

typedef NS_ENUM(char, BlockBasedTableChecksumType) {

BlockBasedTableNoChecksum = 0x0, // not yet supported. Will fail

BlockBasedTableChecksumCRC32c = 0x1,

BlockBasedTableChecksumxxHash = 0x2,

};

@interface RocksDBBlockBasedTableOptions : NSObject

/**

@brief

Indicate to put index/filter blocks to the block cache.

If not specified, each "table reader" object will pre-load index/filter

block during table initialization.

*/

@property (nonatomic, assign) BOOL cacheIndexAndFilterBlocks;

/**

@brief The index type that will be used for this table.

*/

@property (nonatomic, assign) BlockBasedTableIndexType indexType;

/**

@brief

Influence the behavior when kHashSearch is used.

if false, stores a precise prefix to block range mapping

if true, does not store prefix and allows prefix hash collision

(less memory consumption)

*/

@property (nonatomic, assign) BOOL hashIndexAllowCollision;

/**

@brief

Use the specified checksum type. Newly created table files will be

protected with this checksum type. Old table files will still be readable,

even though they have different checksum type.

*/

@property (nonatomic, assign) BlockBasedTableChecksumType checksumType;

/**

@brief

Disable block cache. If this is set to true,

then no block cache should be used, and the block_cache should

point to a nullptr object.

*/

@property (nonatomic, assign) BOOL noBlockCache;

/**

@brief

Use the specified cache for blocks.

If nil, rocksdb will automatically create and use an 8MB internal cache.

@see RocksDBCache

*/

@property (nonatomic, strong, nullable) RocksDBCache *blockCache;

/**

@brief

Use the specified cache for compressed blocks.

@see RocksDBCache

*/

@property (nonatomic, strong, nullable) RocksDBCache *blockCacheCompressed;

/**

@brief

Approximate size of user data packed per block. Note that the

block size specified here corresponds to uncompressed data. The

actual size of the unit read from disk may be smaller if

compression is enabled. This parameter can be changed dynamically.

*/

@property (nonatomic, assign) size_t blockSize;

/**

@brief

This is used to close a block before it reaches the configured

'blockSize'. If the percentage of free space in the current block is less

than this specified number and adding a new record to the block will

exceed the configured block size, then this block will be closed and the

new record will be written to the next block.

*/

@property (nonatomic, assign) int blockSizeDeviation;

/**

@brief

Number of keys between restart points for delta encoding of keys.

This parameter can be changed dynamically.

*/

@property (nonatomic, assign) int blockRestartInterval;

/**

@brief

Use the specified filter policy to reduce disk reads.

@see RocksDBFilterPolicy

*/

@property (nonatomic, strong, nullable) RocksDBFilterPolicy *filterPolicy;

/**

@brief

If true, place whole keys in the filter (not just prefixes).

This must generally be true for gets to be efficient.

*/

@property (nonatomic, assign) BOOL wholeKeyFiltering;

@end

NS_ASSUME_NONNULL_END