open_address_hash_dictionary_handler.h File Reference

#include "../dictionary_types.h"
#include "./../dictionary.h"
#include "../../key_value/kv_system.h"
#include "open_address_hash.h"
#include "open_address_hash_dictionary.h"

Description

The handler for a hash table using linear probing.

Author

Scott Ronald Fazackerley

Copyright

Copyright 2017 The University of British Columbia, IonDB Project Contributors (see AUTHORS.md)

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.

3.Neither the name of the copyright holder nor the names of its contributors

may be used to endorse or promote products derived from this software without specific prior written permission.

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.

Definition in file open_address_hash_dictionary_handler.h.

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Classes
struct	oa_dictionary
	Struct used to for instance of a given dictionary. More...
struct	oadict_equality_cursor
	Dictionary cursor for equality queries. More...

Typedefs
typedef struct oa_dictionary	ion_oa_dictionary_t
	Struct used to for instance of a given dictionary. More...
typedef struct oadict_equality_cursor	ion_oadict_equality_cursor_t
	Dictionary cursor for equality queries. More...

Functions
void	oadict_init (ion_dictionary_handler_t *handler)
	Registers a specific handler for a dictionary instance. More...
ion_status_t	oadict_insert (ion_dictionary_t *dictionary, ion_key_t key, ion_value_t value)
	Inserts a key and value into the dictionary. More...
ion_err_t	oadict_create_dictionary (ion_dictionary_id_t id, ion_key_type_t key_type, ion_key_size_t key_size, ion_value_size_t value_size, ion_dictionary_size_t dictionary_size, ion_dictionary_compare_t compare, ion_dictionary_handler_t *handler, ion_dictionary_t *dictionary)
	Creates an instance of a dictionary. More...
ion_status_t	oadict_delete (ion_dictionary_t *dictionary, ion_key_t key)
	Deletes the key and assoicated value from the dictionary instance. More...
ion_err_t	oadict_delete_dictionary (ion_dictionary_t *dictionary)
	Deletes an instance of the dictionary and associated data. More...
ion_err_t	oadict_destroy_dictionary (ion_dictionary_id_t id)
	Cleans up all files created by the dictionary, and frees any allocated memory, for an already closed dictionary. More...
ion_status_t	oadict_update (ion_dictionary_t *dictionary, ion_key_t key, ion_value_t value)
	Updates the value for a given key. More...
int	oadict_compare (ion_key_t first_key, ion_key_t second_key)
	Compares two key and returns the difference. More...
ion_cursor_status_t	oadict_next (ion_dict_cursor_t *cursor, ion_record_t *record)
	Next function to query and retrieve the next <K,V> that stratifies the predicate of the cursor. More...
ion_boolean_t	oadict_is_equal (ion_dictionary_t *dict, ion_key_t key1, ion_key_t key2)
	Compares two keys and determines if they are equal assuming that they are equal is length (in size). More...
void	oadict_destroy_cursor (ion_dict_cursor_t **cursor)
	Destroys the cursor. More...

Typedef Documentation

typedef struct oa_dictionary ion_oa_dictionary_t

Struct used to for instance of a given dictionary.

typedef struct oadict_equality_cursor ion_oadict_equality_cursor_t

Dictionary cursor for equality queries.

Used when a dictionary supports multiple vvalues for a given key.

        This subtype should be extended when supported for a given
        dictionary.

Function Documentation

int oadict_compare	(	ion_key_t	first_key,
		ion_key_t	second_key
	)

Compares two key and returns the difference.

Compares two key and returns the difference depending on the type of the key defined for the dictionary instance. If the keys are of numeric type, the return value is the difference between the keys. If the value is negative, first_key is smaller than second_key. If return value is positive, then first_key is larger than second_key. If the return value is 0 then first_key is equal to second_key.

If the key type is key_type_char_array then the function memcmp compares the size bytes of memory beginning at a1 against the size bytes of memory beginning at a2. The value returned has the same sign as the difference between the first differing pair of bytes (interpreted as unsigned char objects, then promoted to int).

Parameters

first_key	The first key in the comparison.
second_key	The second key in the comparison.

Returns

The difference between the keys.

ion_err_t oadict_create_dictionary	(	ion_dictionary_id_t	id,
		ion_key_type_t	key_type,
		ion_key_size_t	key_size,
		ion_value_size_t	value_size,
		ion_dictionary_size_t	dictionary_size,
		ion_dictionary_compare_t	compare,
		ion_dictionary_handler_t *	handler,
		ion_dictionary_t *	dictionary
	)

Creates an instance of a dictionary.

Creates as instance of a dictionary given a key_size and value_size, in bytes as well as the dictionary size which is the number of buckets available in the hashmap.

Parameters

id
key_type
key_size	The size of the key in bytes.
value_size	The size of the value in bytes.
dictionary_size	The size of the hashmap in discrete units
compare	Function pointer for the comparison function for the dictionary.
handler	THe handler for the specific dictionary being created.
dictionary	The pointer declared by the caller that will reference the instance of the dictionary created.

Returns

The status of the creation of the dictionary.

Definition at line 349 of file open_address_hash_dictionary_handler.c.

  {
    UNUSED(id);
    /* this is the instance of the hashmap */
    dictionary->instance            = malloc(sizeof(ion_hashmap_t));

    dictionary->instance->compare   = compare;
    dictionary->instance->type      = dictionary_type_open_address_hash_t;

    /* this registers the dictionary the dictionary */
    oah_initialize((ion_hashmap_t *) dictionary->instance, oah_compute_simple_hash, key_type, key_size, value_size, dictionary_size);   /* just pick an arbitary size for testing atm */

    /*TODO The correct comparison operator needs to be bound at run time
     * based on the type of key defined
    */

    if (NULL == handler) {
        return err_uninitialized;
    }

    /* register the correct handler */
    dictionary->handler = handler;

    return 0;
}

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ion_status_t oadict_delete	(	ion_dictionary_t *	dictionary,
		ion_key_t	key
	)

Deletes the key and assoicated value from the dictionary instance.

Parameters

dictionary	The instance of the dictionary to delete from.
key	The key that is to be deleted.

Returns

The status of the deletion

Definition at line 384 of file open_address_hash_dictionary_handler.c.

  {
    return oah_delete((ion_hashmap_t *) dictionary->instance, key);
}

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ion_err_t oadict_delete_dictionary

(

ion_dictionary_t *

dictionary

)

Deletes an instance of the dictionary and associated data.

Parameters

dictionary

The instance of the dictionary to delete.

Returns

The status of the dictionary deletion.

Definition at line 392 of file open_address_hash_dictionary_handler.c.

  {
    ion_err_t result = oah_destroy((ion_hashmap_t *) dictionary->instance);

    free(dictionary->instance);
    dictionary->instance = NULL;/* When releasing memory, set pointer to NULL */
    return result;
}

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void oadict_destroy_cursor

(

ion_dict_cursor_t **

cursor

)

Destroys the cursor.

Destroys the cursor when the user is finished with it. The destroy function will free up internally allocated memory as well as freeing up any reference to the cursor itself. Cursor pointers will be set to NULL as per ION_DB specification for de-allocated pointers.

Parameters

cursor

pointer to cursor.

Definition at line 487 of file open_address_hash_dictionary_handler.c.

  {
    (*cursor)->predicate->destroy(&(*cursor)->predicate);
    free(*cursor);
    *cursor = NULL;
}

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ion_err_t oadict_destroy_dictionary

(

ion_dictionary_id_t

id

)

Cleans up all files created by the dictionary, and frees any allocated memory, for an already closed dictionary.

Parameters

id	The identifier identifying the dictionary to delete.

Returns

The resulting status of the operation.

Definition at line 403 of file open_address_hash_dictionary_handler.c.

  {
    UNUSED(id);
    return err_not_implemented;
}

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void oadict_init

(

ion_dictionary_handler_t *

handler

)

Registers a specific handler for a dictionary instance.

Registers functions for handlers. This only needs to be called once for each type of dictionary that is present.

Parameters

handler

The handler for the dictionary instance that is to be initialized.

Definition at line 324 of file open_address_hash_dictionary_handler.c.

  {
    handler->insert             = oadict_insert;
    handler->create_dictionary  = oadict_create_dictionary;
    handler->get                = oadict_get;
    handler->update             = oadict_update;
    handler->find               = oadict_find;
    handler->remove             = oadict_delete;
    handler->delete_dictionary  = oadict_delete_dictionary;
    handler->destroy_dictionary = oadict_destroy_dictionary;
    handler->close_dictionary   = oadict_close_dictionary;
    handler->open_dictionary    = oadict_open_dictionary;
}

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ion_status_t oadict_insert	(	ion_dictionary_t *	dictionary,
		ion_key_t	key,
		ion_value_t	value
	)

Inserts a key and value into the dictionary.

Parameters

dictionary	The dictionary instance to insert the value into.
key	The key to use.
value	The value to use.

Returns

The status on the insertion of the record.

Definition at line 340 of file open_address_hash_dictionary_handler.c.

  {
    return oah_insert((ion_hashmap_t *) dictionary->instance, key, value);
}

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ion_boolean_t oadict_is_equal	(	ion_dictionary_t *	dict,
		ion_key_t	key1,
		ion_key_t	key2
	)

Compares two keys and determines if they are equal assuming that they are equal is length (in size).

Parameters

dict	The map the keys are associated with.
key1	The first key for comparison.
key2	The second key for comparison.

Returns

If the keys are equal.

Definition at line 473 of file open_address_hash_dictionary_handler.c.

  {
    if (memcmp(key1, key2, (((ion_hashmap_t *) dict->instance)->super.record.key_size)) == ION_IS_EQUAL) {
        return boolean_true;
    }
    else {
        return boolean_false;
    }
}

ion_cursor_status_t oadict_next	(	ion_dict_cursor_t *	cursor,
		ion_record_t *	record
	)

Next function to query and retrieve the next <K,V> that stratifies the predicate of the cursor.

Parameters

cursor

The cursor to iterate over the results.

Returns

The status of the cursor. Next function to query and retrieve the next <K,V> that stratifies the predicate of the cursor.

Parameters

cursor	The cursor to iterate over the results.
record

Returns

The status of the cursor.

Definition at line 420 of file open_address_hash_dictionary_handler.c.

  {
    ion_oadict_cursor_t *oadict_cursor = (ion_oadict_cursor_t *) cursor;

    /* check the status of the cursor and if it is not valid or at the end, just exit */
    if (cursor->status == cs_cursor_uninitialized) {
        return cursor->status;
    }
    else if (cursor->status == cs_end_of_results) {
        return cursor->status;
    }
    else if ((cursor->status == cs_cursor_initialized) || (cursor->status == cs_cursor_active)) {
        /* cursor is active and results have never been accessed */
        /* extract reference to map */
        ion_hashmap_t *hash_map = ((ion_hashmap_t *) cursor->dictionary->instance);

        /* assume that the value has been pre-allocated */
        /* compute length of data record stored in map */
        int data_length = hash_map->super.record.key_size + hash_map->super.record.value_size;

        if (cursor->status == cs_cursor_active) {
            /* find the next valid entry */

            /* scan and determine what to do? */
            if (cs_end_of_results == oadict_scan(oadict_cursor)) {
                /* Then this is the end and there are no more results */
                cursor->status = cs_end_of_results;
                return cursor->status;
            }
        }
        else {
            /* if the cursor is initialized but not active, then just read the data and set cursor active */
            cursor->status = cs_cursor_active;
        }

        /* the results are now ready //reference item at given position */
        ion_hash_bucket_t *item = (((ion_hash_bucket_t *) ((hash_map->entry + (data_length + SIZEOF(STATUS)) * oadict_cursor->current /*idx*/))));

        memcpy(record->key, (item->data), hash_map->super.record.key_size);

        memcpy(record->value, (item->data + hash_map->super.record.key_size), hash_map->super.record.value_size);

        /* and update current cursor position */
        return cursor->status;
    }

    /* and if you get this far, the cursor is invalid */
    return cs_invalid_cursor;
}

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ion_status_t oadict_update	(	ion_dictionary_t *	dictionary,
		ion_key_t	key,
		ion_value_t	value
	)

Updates the value for a given key.

Updates the value for a given key. If the key does not currently exist in the hashmap, it will be created and the value sorted.

Parameters

dictionary	The instance of the dictionary to be updated.
key	The key that is to be updated.
value	The value that is to be updated.

Returns

The status of the update.

Definition at line 411 of file open_address_hash_dictionary_handler.c.

  {
    return oah_update((ion_hashmap_t *) dictionary->instance, key, value);
}

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