# Copyright (c) 2022 Meta
#
# SPDX-License-Identifier: Apache-2.0

menu "Hashmap (Hash Table) Support"

config SYS_HASH_MAP
	bool "Hashmap support"
	help
	  Support for Hashmaps (a.k.a. Hash Tables).

	  Hashmaps are data structures that are used when insertion, removal, and
	  lookup of key-value pairs must be done in O(1) time (on average).

if SYS_HASH_MAP

config SYS_HASH_MAP_SC
	bool "Separate-Chaining Hashmap"
	help
	  Separate-Chaining Hashmaps implement each bucket as a linked-list.

	  They are perhaps more useful on resource-constrained systems where
	  large contiguous memory regions are scarce.

	  The main disadvantage of Separate-Chaining Hashmaps are that their
	  use tends to incur more cache-misses as nodes are spread throughout
	  the heap.

config SYS_HASH_MAP_OA_LP
	bool "Open-Addressing / Linear Probe Hashmap"
	help
	  Open-Addressing Hashmaps do not chain entries together but instead
	  store all entries in the table itself which is a contiguously allocated
	  memory region.

	  The main advantage of Open-Addressing Hashmaps are due to their
	  contiguous allocation which improves performance on systems with
	  memory caching.

config SYS_HASH_MAP_CXX
	bool "C++ Hashmap"
	select CPP
	select REQUIRES_FULL_LIBCPP
	select CPP_EXCEPTIONS
	help
	  This enables a C wrapper around the C++ std::unordered_map.

	  It is mainly used for benchmarking purposes.

choice SYS_HASH_MAP_CHOICE
	prompt "Default hashmap implementation"
	default SYS_HASH_MAP_CHOICE_SC

config SYS_HASH_MAP_CHOICE_SC
	bool "Default hash is Separate-Chaining"
	select SYS_HASH_MAP_SC

config SYS_HASH_MAP_CHOICE_OA_LP
	bool "Default hash is Open-Addressing / Linear Probe"
	select SYS_HASH_MAP_OA_LP

config SYS_HASH_MAP_CHOICE_CXX
	bool "Default hash is C++"
	select SYS_HASH_MAP_CXX

endchoice # SYS_HASH_MAP_CHOICE

endif

endmenu