Documentation

class Ord key => BTree key value pointer whereSource

Describes functions for accessing a B-tree on a Filesystem. These functions are used to write portable, reusable code for properly managing any B-tree.

Methods

btOrder Source

Arguments

:: (Num a, Device m h)
=> Filesystem m h
-> (key, value, pointer)	This parameter is included for the sole purpose of selecting which instance to use. Its value should be assumed undefined.
-> a

Returns the optimal Knuth order for the given filesystem.

btGet :: Device m h => Filesystem m h -> pointer -> m (BNode key value pointer)Source

Retrieves a BNode from storage. Might throw an exception (or use Maybe) in the future if the node failed verification (via a checksum or similar), but currently it does not.

btPut :: Device m h => Filesystem m h -> pointer -> BNode key value pointer -> m ()Source

Places a BNode into storage. Attempting to write a BNode to an unallocated part of storage may result in an exception in some implementations.

btAllocate :: Device m h => Filesystem m h -> m pointerSource

Allocates and returns a pointer to a space where a BNode may be stored.

btFree :: Device m h => Filesystem m h -> pointer -> m ()Source

Frees the space used by a BNode.

data BTree key value pointer => BNode key value pointer Source

Describes a node of a B-tree in memory.

Constructors

BNode
Fields bnKeys :: [key] The keys used for branching in the tree. Must be comparable (`Ord`). bnValues :: [value] The values associated with the keys. These values are not altered or inspected by any portable code. bnChildren :: [pointer] The pointers for each of the branches of the node. Must be valid for use with the functions defined in the `BTree` class.