151 lines
3.5 KiB
C
151 lines
3.5 KiB
C
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/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* Hash map.
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*/
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#ifndef __HASHMAP_H
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#define __HASHMAP_H
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#include <stdbool.h>
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#include <stdlib.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** A hash map. */
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typedef struct Hashmap Hashmap;
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/**
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* Creates a new hash map. Returns NULL if memory allocation fails.
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*
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* @param initialCapacity number of expected entries
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* @param hash function which hashes keys
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* @param equals function which compares keys for equality
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*/
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Hashmap* hashmapCreate(size_t initialCapacity,
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int (*hash)(void* key), bool (*equals)(void* keyA, void* keyB));
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/**
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* Frees the hash map. Does not free the keys or values themselves.
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*/
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void hashmapFree(Hashmap* map);
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/**
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* Hashes the memory pointed to by key with the given size. Useful for
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* implementing hash functions.
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*/
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int hashmapHash(void* key, size_t keySize);
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/**
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* Puts value for the given key in the map. Returns pre-existing value if
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* any.
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*
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* If memory allocation fails, this function returns NULL, the map's size
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* does not increase, and errno is set to ENOMEM.
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*/
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void* hashmapPut(Hashmap* map, void* key, void* value);
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/**
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* Gets a value from the map. Returns NULL if no entry for the given key is
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* found or if the value itself is NULL.
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*/
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void* hashmapGet(Hashmap* map, void* key);
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/**
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* Returns true if the map contains an entry for the given key.
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*/
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bool hashmapContainsKey(Hashmap* map, void* key);
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/**
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* Gets the value for a key. If a value is not found, this function gets a
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* value and creates an entry using the given callback.
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*
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* If memory allocation fails, the callback is not called, this function
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* returns NULL, and errno is set to ENOMEM.
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*/
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void* hashmapMemoize(Hashmap* map, void* key,
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void* (*initialValue)(void* key, void* context), void* context);
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/**
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* Removes an entry from the map. Returns the removed value or NULL if no
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* entry was present.
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*/
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void* hashmapRemove(Hashmap* map, void* key);
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/**
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* Gets the number of entries in this map.
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*/
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size_t hashmapSize(Hashmap* map);
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/**
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* Invokes the given callback on each entry in the map. Stops iterating if
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* the callback returns false.
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*/
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void hashmapForEach(Hashmap* map,
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bool (*callback)(void* key, void* value, void* context),
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void* context);
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/**
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* Concurrency support.
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*/
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/**
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* Locks the hash map so only the current thread can access it.
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*/
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void hashmapLock(Hashmap* map);
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/**
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* Unlocks the hash map so other threads can access it.
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*/
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void hashmapUnlock(Hashmap* map);
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/**
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* Key utilities.
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*/
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/**
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* Hashes int keys. 'key' is a pointer to int.
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*/
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int hashmapIntHash(void* key);
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/**
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* Compares two int keys for equality.
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*/
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bool hashmapIntEquals(void* keyA, void* keyB);
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/**
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* For debugging.
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*/
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/**
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* Gets current capacity.
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*/
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size_t hashmapCurrentCapacity(Hashmap* map);
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/**
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* Counts the number of entry collisions.
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*/
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size_t hashmapCountCollisions(Hashmap* map);
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#ifdef __cplusplus
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}
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#endif
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#endif /* __HASHMAP_H */
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