177 lines
4.5 KiB
C
177 lines
4.5 KiB
C
/*
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* Copyright (c) 2009-2014 Petri Lehtinen <petri@digip.org>
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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#ifndef HASHTABLE_H
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#define HASHTABLE_H
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#include <stdlib.h>
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#include "jansson.h"
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struct hashtable_list {
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struct hashtable_list *prev;
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struct hashtable_list *next;
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};
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/* "pair" may be a bit confusing a name, but think of it as a
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key-value pair. In this case, it just encodes some extra data,
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too */
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struct hashtable_pair {
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struct hashtable_list list;
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struct hashtable_list ordered_list;
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size_t hash;
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json_t *value;
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char key[1];
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};
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struct hashtable_bucket {
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struct hashtable_list *first;
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struct hashtable_list *last;
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};
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typedef struct hashtable {
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size_t size;
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struct hashtable_bucket *buckets;
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size_t order; /* hashtable has pow(2, order) buckets */
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struct hashtable_list list;
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struct hashtable_list ordered_list;
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} hashtable_t;
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#define hashtable_key_to_iter(key_) \
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(&(container_of(key_, struct hashtable_pair, key)->ordered_list))
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/**
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* hashtable_init - Initialize a hashtable object
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*
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* @hashtable: The (statically allocated) hashtable object
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*
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* Initializes a statically allocated hashtable object. The object
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* should be cleared with hashtable_close when it's no longer used.
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*
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* Returns 0 on success, -1 on error (out of memory).
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*/
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int hashtable_init(hashtable_t *hashtable);
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/**
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* hashtable_close - Release all resources used by a hashtable object
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*
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* @hashtable: The hashtable
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*
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* Destroys a statically allocated hashtable object.
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*/
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void hashtable_close(hashtable_t *hashtable);
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/**
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* hashtable_set - Add/modify value in hashtable
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*
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* @hashtable: The hashtable object
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* @key: The key
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* @serial: For addition order of keys
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* @value: The value
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*
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* If a value with the given key already exists, its value is replaced
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* with the new value. Value is "stealed" in the sense that hashtable
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* doesn't increment its refcount but decreases the refcount when the
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* value is no longer needed.
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*
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* Returns 0 on success, -1 on failure (out of memory).
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*/
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int hashtable_set(hashtable_t *hashtable, const char *key, json_t *value);
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/**
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* hashtable_get - Get a value associated with a key
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*
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* @hashtable: The hashtable object
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* @key: The key
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*
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* Returns value if it is found, or NULL otherwise.
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*/
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void *hashtable_get(hashtable_t *hashtable, const char *key);
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/**
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* hashtable_del - Remove a value from the hashtable
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*
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* @hashtable: The hashtable object
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* @key: The key
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*
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* Returns 0 on success, or -1 if the key was not found.
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*/
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int hashtable_del(hashtable_t *hashtable, const char *key);
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/**
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* hashtable_clear - Clear hashtable
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*
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* @hashtable: The hashtable object
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*
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* Removes all items from the hashtable.
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*/
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void hashtable_clear(hashtable_t *hashtable);
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/**
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* hashtable_iter - Iterate over hashtable
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*
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* @hashtable: The hashtable object
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*
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* Returns an opaque iterator to the first element in the hashtable.
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* The iterator should be passed to hashtable_iter_* functions.
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* The hashtable items are not iterated over in any particular order.
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*
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* There's no need to free the iterator in any way. The iterator is
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* valid as long as the item that is referenced by the iterator is not
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* deleted. Other values may be added or deleted. In particular,
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* hashtable_iter_next() may be called on an iterator, and after that
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* the key/value pair pointed by the old iterator may be deleted.
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*/
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void *hashtable_iter(hashtable_t *hashtable);
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/**
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* hashtable_iter_at - Return an iterator at a specific key
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*
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* @hashtable: The hashtable object
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* @key: The key that the iterator should point to
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*
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* Like hashtable_iter() but returns an iterator pointing to a
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* specific key.
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*/
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void *hashtable_iter_at(hashtable_t *hashtable, const char *key);
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/**
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* hashtable_iter_next - Advance an iterator
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*
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* @hashtable: The hashtable object
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* @iter: The iterator
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*
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* Returns a new iterator pointing to the next element in the
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* hashtable or NULL if the whole hastable has been iterated over.
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*/
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void *hashtable_iter_next(hashtable_t *hashtable, void *iter);
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/**
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* hashtable_iter_key - Retrieve the key pointed by an iterator
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*
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* @iter: The iterator
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*/
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void *hashtable_iter_key(void *iter);
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/**
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* hashtable_iter_value - Retrieve the value pointed by an iterator
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*
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* @iter: The iterator
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*/
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void *hashtable_iter_value(void *iter);
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/**
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* hashtable_iter_set - Set the value pointed by an iterator
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*
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* @iter: The iterator
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* @value: The value to set
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*/
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void hashtable_iter_set(void *iter, json_t *value);
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#endif
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