BTree

B-Tree key/value database file access class.

This class provides a high performance key/value storage mechanism that stores data to file. A B-tree is a self-balancing tree data structure that keeps data sorted and allows searches, sequential access, insertions, and deletions in logarithmic time.

Constants

SIZEOF_HEADER

public const SIZEOF_HEADER = 6

HEADER

public const HEADER = '"\xffbtree"'

NODE_SLOTS

public const NODE_SLOTS = 16

SIZEOF_INT

public const SIZEOF_INT = 4

KVNODE

public const KVNODE = 'kv'

KPNODE

public const KPNODE = 'kp'

NODECHACHE_SIZE

public const NODECHACHE_SIZE = 64

Properties

file

public File $file

nodecache

private array $nodecache

readOnly

private bool $readOnly

Methods

__construct

Use static method open() to get instance.

public __construct(string $file, bool $readOnly = false): void

Parameters

Parameter	Type	Description
$file	string
$readOnly	bool

open

Open the file for access.

public open(string $file, bool $readOnly = false): bool

Parameters

Parameter	Type	Description
$file	string
$readOnly	bool

close

Close the file.

public close(): bool

resetBTreeFile

The the B-Tree source file.

public resetBTreeFile(): bool

get

Get value by key.

public get(string $key): void

Parameters

Parameter	Type	Description
$key	string	The key to return data for

range

Get all values where startkey <= key < endkey.

public range(string $startkey, string $endkey): void

To get all data, use:

$values = $btree->range("\x00", "\xff");

Parameters

Parameter	Type	Description
$startkey	string
$endkey	string

set

Set value under given key.

public set(string $key, mixed $value): bool

Parameters

Parameter	Type	Description
$key	string	the key to store the value under
$value	mixed	The value to store. A NULL value deletes given key.

remove

public remove(string $key): bool

Parameters

Parameter	Type	Description
$key	string

has

Check if a given key exists in the database.

public has(string $key): bool

Parameters

Parameter	Type	Description
$key	string

keys

Get a list of all available keys in the database.

public keys(): void

Warning: Unlike a search this will hit almost every part of the database file and can be a bit slow.

leaves

Get positions of all leaves.

public leaves(): void

compact

Remove old nodes from BTree file.

public compact(): void

dropCache

public dropCache(): void

toArray

public toArray(): void

lookup

Look up a key.

private lookup(string $key, ?string $nodeType, ?array $node, bool $): void

Parameters

Parameter	Type	Description
$key	string
$nodeType	string
$node	array
$	bool

leafHunt

Find positions of all leaves.

private leafHunt(int $p): void

Parameters

Parameter	Type	Description
$p	int	pointer to node

copyTo

Copy node from opened file to another.

private copyTo(File $to, ?string $nodeType, ?array $node): ?int

Parameters

Parameter	Type	Description
$to	File	The file to copy everything to
$nodeType	string
$node	array

root

Get root node.

private root(): void

rootHunt

Try to get position of root.

private rootHunt(): ?int

node

Get node.

private node(int $p): void

Parameters

Parameter	Type	Description
$p	int	Pointer to node (offset in file)

serialize

private serialize(string $type, array $node): string

Parameters

Parameter	Type	Description
$type	string
$node	array

unserialize

private unserialize(string $str): void

Parameters

Parameter	Type	Description
$str	string

header

private header(File $file,  $root): void

Parameters

Parameter	Type	Description
$file	File
$root	``````

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