2022-12-31 03:18:05 +08:00
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# Copyright (c) 2022 Meta
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#
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# SPDX-License-Identifier: Apache-2.0
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menu "Hashmap (Hash Table) Support"
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config SYS_HASH_MAP
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bool "Hashmap support"
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help
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Support for Hashmaps (a.k.a. Hash Tables).
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Hashmaps are data structures that are used when insertion, removal, and
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lookup of key-value pairs must be done in O(1) time (on average).
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if SYS_HASH_MAP
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config SYS_HASH_MAP_SC
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bool "Separate-Chaining Hashmap"
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help
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Separate-Chaining Hashmaps implement each bucket as a linked-list.
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They are perhaps more useful on resource-constrained systems where
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large contiguous memory regions are scarce.
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The main disadvantage of Separate-Chaining Hashmaps are that their
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use tends to incur more cache-misses as nodes are spread throughout
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the heap.
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config SYS_HASH_MAP_OA_LP
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bool "Open-Addressing / Linear Probe Hashmap"
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help
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Open-Addressing Hashmaps do not chain entries together but instead
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store all entries in the table itself which is a contiguously allocated
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memory region.
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The main advantage of Open-Addressing Hashmaps are due to their
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contiguous allocation which improves performance on systems with
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memory caching.
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config SYS_HASH_MAP_CXX
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bool "C++ Hashmap"
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2023-07-26 19:16:31 +08:00
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select CPP
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select REQUIRES_FULL_LIBCPP
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select CPP_EXCEPTIONS
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2022-12-31 03:18:05 +08:00
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help
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This enables a C wrapper around the C++ std::unordered_map.
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It is mainly used for benchmarking purposes.
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choice SYS_HASH_MAP_CHOICE
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prompt "Default hashmap implementation"
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default SYS_HASH_MAP_CHOICE_SC
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config SYS_HASH_MAP_CHOICE_SC
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bool "Default hash is Separate-Chaining"
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select SYS_HASH_MAP_SC
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config SYS_HASH_MAP_CHOICE_OA_LP
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bool "Default hash is Open-Addressing / Linear Probe"
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select SYS_HASH_MAP_OA_LP
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config SYS_HASH_MAP_CHOICE_CXX
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bool "Default hash is C++"
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select SYS_HASH_MAP_CXX
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endchoice # SYS_HASH_MAP_CHOICE
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endif
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endmenu
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