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 /*

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

  *

  * Copyright 2017 Mike Becker, Olaf Wintermann All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   1. Redistributions of source code must retain the above copyright

  *      notice, this list of conditions and the following disclaimer.

  *

  *   2. Redistributions in binary form must reproduce the above copyright

  *      notice, this list of conditions and the following disclaimer in the

  *      documentation and/or other materials provided with the distribution.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

  * POSSIBILITY OF SUCH DAMAGE.

  */

 /**

  * @file map.h

  * 

  * Hash map implementation.

  * 

  * This implementation uses murmur hash 2 and separate chaining with linked

  * lists.

  * 

  * @author Mike Becker

  * @author Olaf Wintermann

  */

 #ifndef UCX_MAP_H

 #define	UCX_MAP_H

 #include "ucx.h"

 #include "string.h"

 #include "allocator.h"

 #include <stdio.h>

 #ifdef	__cplusplus

 extern "C" {

 #endif

 /**

  * Loop statement for UCX maps.

  * 

  * The <code>key</code> variable is implicitly defined, but the

  * <code>value</code> variable must be already declared as type information

  * cannot be inferred.

  * 

  * @param key the variable name for the key

  * @param value the variable name for the value

  * @param iter a UcxMapIterator

  * @see ucx_map_iterator()

  */

 #define UCX_MAP_FOREACH(key,value,iter) \

         for(UcxKey key;ucx_map_iter_next(&iter,&key, (void**)&value);)

 /** Type for the UCX map. @see UcxMap */

 typedef struct UcxMap          UcxMap;

 /** Type for a key of a UcxMap. @see UcxKey */

 typedef struct UcxKey          UcxKey;

 /** Type for an element of a UcxMap. @see UcxMapElement */

 typedef struct UcxMapElement   UcxMapElement;

 /** Type for an iterator over a UcxMap. @see UcxMapIterator */

 typedef struct UcxMapIterator  UcxMapIterator;

 /** Structure for the UCX map. */

 struct UcxMap {

     /** An allocator that is used for the map elements. */

     UcxAllocator  *allocator;

     /** The array of map element lists. */

     UcxMapElement **map;

     /** The size of the map is the length of the element list array. */

     size_t        size;

     /** The count of elements currently stored in this map. */

     size_t        count;

 };

 /** Structure to publicly denote a key of a UcxMap. */

 struct UcxKey {

     /** The key data. */

     const void *data;

     /** The length of the key data. */

     size_t     len;

     /** A cache for the hash value of the key data. */

     int        hash;

 };

 /** Internal structure for a key of a UcxMap. */

 struct UcxMapKey {

     /** The key data. */

     void    *data;

     /** The length of the key data. */

     size_t  len;

     /** The hash value of the key data. */

     int     hash;

 };

 /** Structure for an element of a UcxMap. */

 struct UcxMapElement {

     /** The value data. */

     void              *data;

     /** A pointer to the next element in the current list. */

     UcxMapElement     *next;

     /** The corresponding key. */

     struct UcxMapKey  key;

 };

 /** Structure for an iterator over a UcxMap. */

 struct UcxMapIterator {

     /** The map to iterate over. */

     UcxMap        *map;

     /** The current map element. */

     UcxMapElement *cur;

     /**

      * The current index of the element list array.

      * <b>Attention: </b> this is <b>NOT</b> the element index! Do <b>NOT</b>

      * manually iterate over the map by increasing this index. Use

      * ucx_map_iter_next().

      * @see UcxMap.map*/

     size_t        index;

 };

 /**

  * Creates a new hash map with the specified size.

  * @param size the size of the hash map

  * @return a pointer to the new hash map

  */

 UcxMap *ucx_map_new(size_t size);

 /**

  * Creates a new hash map with the specified size using a UcxAllocator.

  * @param allocator the allocator to use

  * @param size the size of the hash map

  * @return a pointer to the new hash map

  */

 UcxMap *ucx_map_new_a(UcxAllocator *allocator, size_t size);

 /**

  * Frees a hash map.

  * 

  * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content()

  * before calling this function to achieve that.

  * 

  * @param map the map to be freed

  * @see ucx_map_free_content()

  */

 void ucx_map_free(UcxMap *map);

 /**

  * Frees the contents of a hash map.

  * 

  * This is a convenience function that iterates over the map and passes all

  * values to the specified destructor function.

  * 

  * If no destructor is specified (<code>NULL</code>), the free() function of

  * the map's own allocator is used.

  * 

  * You must ensure, that it is valid to pass each value in the map to the same

  * destructor function.

  * 

  * You should free or clear the map afterwards, as the contents will be invalid.

  * 

  * @param map for which the contents shall be freed

  * @param destr optional pointer to a destructor function

  * @see ucx_map_free()

  * @see ucx_map_clear()

  */

 void ucx_map_free_content(UcxMap *map, ucx_destructor destr);

 /**

  * Clears a hash map.

  * 

  * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content()

  * before calling this function to achieve that.

  * 

  * @param map the map to be cleared

  * @see ucx_map_free_content()

  */

 void ucx_map_clear(UcxMap *map);

 /**

  * Copies contents from a map to another map using a copy function.

  * 

  * <b>Note:</b> The destination map does not need to be empty. However, if it

  * contains data with keys that are also present in the source map, the contents

  * are overwritten.

  * 

  * @param from the source map

  * @param to the destination map

  * @param fnc the copy function or <code>NULL</code> if the pointer address

  * shall be copied

  * @param data additional data for the copy function

  * @return 0 on success or a non-zero value on memory allocation errors

  */

 int ucx_map_copy(UcxMap *from, UcxMap *to, copy_func fnc, void *data);

 /**

  * Clones the map and rehashes if necessary.

  * 

  * <b>Note:</b> In contrast to ucx_map_rehash() the load factor is irrelevant.

  * This function <i>always</i> ensures a new UcxMap.size of at least

  * 2.5*UcxMap.count.

  * 

  * @param map the map to clone

  * @param fnc the copy function to use or <code>NULL</code> if the new and

  * the old map shall share the data pointers

  * @param data additional data for the copy function

  * @return the cloned map

  * @see ucx_map_copy()

  */

 UcxMap *ucx_map_clone(UcxMap *map, copy_func fnc, void *data);

 /**

  * Increases size of the hash map, if necessary.

  * 

  * The load value is 0.75*UcxMap.size. If the element count exceeds the load

  * value, the map needs to be rehashed. Otherwise no action is performed and

  * this function simply returns 0.

  * 

  * The rehashing process ensures, that the UcxMap.size is at least

  * 2.5*UcxMap.count. So there is enough room for additional elements without

  * the need of another soon rehashing.

  * 

  * You can use this function to dramatically increase access performance.

  * 

  * @param map the map to rehash

  * @return 1, if a memory allocation error occurred, 0 otherwise

  */

 int ucx_map_rehash(UcxMap *map);

 /**

  * Puts a key/value-pair into the map.

  * 

  * @param map the map

  * @param key the key

  * @param value the value

  * @return 0 on success, non-zero value on failure

  */

 int ucx_map_put(UcxMap *map, UcxKey key, void *value);

 /**

  * Retrieves a value by using a key.

  * 

  * @param map the map

  * @param key the key

  * @return the value

  */

 void* ucx_map_get(UcxMap *map, UcxKey key);

 /**

  * Removes a key/value-pair from the map by using the key.

  * 

  * @param map the map

  * @param key the key

  * @return the removed value

  */

 void* ucx_map_remove(UcxMap *map, UcxKey key);

 /**

  * Shorthand for putting data with a sstr_t key into the map.

  * @param map the map

  * @param key the key

  * @param value the value

  * @return 0 on success, non-zero value on failure

  * @see ucx_map_put()

  */

 #define ucx_map_sstr_put(map, key, value) \

     ucx_map_put(map, ucx_key(key.ptr, key.length), (void*)value)

 /**

  * Shorthand for putting data with a C string key into the map.

  * @param map the map

  * @param key the key

  * @param value the value

  * @return 0 on success, non-zero value on failure

  * @see ucx_map_put()

  */

 #define ucx_map_cstr_put(map, key, value) \

     ucx_map_put(map, ucx_key(key, strlen(key)), (void*)value)

 /**

  * Shorthand for putting data with an integer key into the map.

  * @param map the map

  * @param key the key

  * @param value the value

  * @return 0 on success, non-zero value on failure

  * @see ucx_map_put()

  */

 #define ucx_map_int_put(map, key, value) \

     ucx_map_put(map, ucx_key(&key, sizeof(key)), (void*)value)

 /**

  * Shorthand for getting data from the map with a sstr_t key.

  * @param map the map

  * @param key the key

  * @return the value

  * @see ucx_map_get()

  */

 #define ucx_map_sstr_get(map, key) \

     ucx_map_get(map, ucx_key(key.ptr, key.length))

 /**

  * Shorthand for getting data from the map with a C string key.

  * @param map the map

  * @param key the key

  * @return the value

  * @see ucx_map_get()

  */

 #define ucx_map_cstr_get(map, key) \

     ucx_map_get(map, ucx_key(key, strlen(key)))

 /**

  * Shorthand for getting data from the map with an integer key.

  * @param map the map

  * @param key the key

  * @return the value

  * @see ucx_map_get()

  */

 #define ucx_map_int_get(map, key) \

     ucx_map_get(map, ucx_key(&key, sizeof(int)))

 /**

  * Shorthand for removing data from the map with a sstr_t key.

  * @param map the map

  * @param key the key

  * @return the removed value

  * @see ucx_map_remove()

  */

 #define ucx_map_sstr_remove(map, key) \

     ucx_map_remove(map, ucx_key(key.ptr, key.length))

 /**

  * Shorthand for removing data from the map with a C string key.

  * @param map the map

  * @param key the key

  * @return the removed value

  * @see ucx_map_remove()

  */

 #define ucx_map_cstr_remove(map, key) \

     ucx_map_remove(map, ucx_key(key, strlen(key)))

 /**

  * Shorthand for removing data from the map with an integer key.

  * @param map the map

  * @param key the key

  * @return the removed value

  * @see ucx_map_remove()

  */

 #define ucx_map_int_remove(map, key) \

     ucx_map_remove(map, ucx_key(&key, sizeof(key)))

 /**

  * Creates a UcxKey based on the given data.

  * 

  * This function implicitly computes the hash.

  * 

  * @param data the data for the key

  * @param len the length of the data

  * @return a UcxKey with implicitly computed hash

  * @see ucx_hash()

  */

 UcxKey ucx_key(const void *data, size_t len);

 /**

  * Computes a murmur hash-2.

  * 

  * @param data the data to hash

  * @param len the length of the data

  * @return the murmur hash-2 of the data

  */

 int ucx_hash(const char *data, size_t len);

 /**

  * Creates an iterator for a map.

  * 

  * <b>Note:</b> A UcxMapIterator iterates over all elements in all element

  * lists successively. Therefore the order highly depends on the key hashes and

  * may vary under different map sizes. So generally you may <b>NOT</b> rely on

  * the iteration order.

  * 

  * <b>Note:</b> The iterator is <b>NOT</b> initialized. You need to call

  * ucx_map_iter_next() at least once before accessing any information. However,

  * it is not recommended to access the fields of a UcxMapIterator directly.

  * 

  * @param map the map to create the iterator for

  * @return an iterator initialized on the first element of the

  * first element list

  * @see ucx_map_iter_next()

  */

 UcxMapIterator ucx_map_iterator(UcxMap *map);

 /**

  * Proceeds to the next element of the map (if any).

  * 

  * Subsequent calls on the same iterator proceed to the next element and

  * store the key/value-pair into the memory specified as arguments of this

  * function.

  * 

  * If no further elements are found, this function returns zero and leaves the

  * last found key/value-pair in memory.

  * 

  * @param iterator the iterator to use

  * @param key a pointer to the memory where to store the key

  * @param value a pointer to the memory where to store the value

  * @return 1, if another element was found, 0 if all elements has been processed

  * @see ucx_map_iterator()

  */

 int ucx_map_iter_next(UcxMapIterator *iterator, UcxKey *key, void **value);

 #ifdef	__cplusplus

 }

 #endif

 #endif	/* UCX_MAP_H */