Data Structures | Defines | Functions

Simple hash table
[Hash functions]

Data Structures

struct  di_hash_table
 Hash table. More...
struct  di_hash_node
 Node of a hash table. More...

Defines

#define HASH_TABLE_RESIZE(hash_table)
#define HASH_TABLE_MIN_SIZE   11
#define HASH_TABLE_MAX_SIZE   13845163
#define CLAMP(x, low, high)   (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))

Functions

di_hash_table * di_hash_table_new (di_hash_func hash_func, di_equal_func key_equal_func)
di_hash_table * di_hash_table_new_full (di_hash_func hash_func, di_equal_func key_equal_func, di_destroy_notify key_destroy_func, di_destroy_notify value_destroy_func)
void di_hash_table_destroy (di_hash_table *hash_table)
void di_hash_table_insert (di_hash_table *hash_table, void *key, void *value)
void * di_hash_table_lookup (di_hash_table *hash_table, const void *key)
void di_hash_table_foreach (di_hash_table *hash_table, di_hfunc *func, void *user_data)
di_ksize_t di_hash_table_size (di_hash_table *hash_table)
static void internal_di_hash_table_resize (di_hash_table *hash_table)
static di_hash_node ** internal_di_hash_table_lookup_node (di_hash_table *hash_table, const void *key)
static di_hash_node * internal_di_hash_node_new (di_hash_table *hash_table, void *key, void *value)
static void internal_di_hash_node_destroy (di_hash_node *hash_node, di_destroy_notify key_destroy_func, di_destroy_notify value_destroy_func) __attribute__((unused))
static void internal_di_hash_nodes_destroy (di_hash_node *hash_node, di_destroy_notify key_destroy_func, di_destroy_notify value_destroy_func)

Define Documentation

#define CLAMP (   x,
  low,
  high 
)    (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))

For internal use only.

Parameters:
x value
low low bound
high high bound
Returns:
a value between low and high
#define HASH_TABLE_MAX_SIZE   13845163

For internal use only.

The maximal hash table size

#define HASH_TABLE_MIN_SIZE   11

For internal use only.

The minimal hash table size

#define HASH_TABLE_RESIZE (   hash_table  ) 
Value:
if ((hash_table->size >= 3 * hash_table->nnodes &&      \
      hash_table->size > HASH_TABLE_MIN_SIZE) ||        \
    (3 * hash_table->size <= hash_table->nnodes &&      \
     hash_table->size < HASH_TABLE_MAX_SIZE))           \
     internal_di_hash_table_resize (hash_table);

For internal use only.

Defines if a resize is necessary

Parameters:
hash_table a di_hash_table

Referenced by di_hash_table_insert().

Function Documentation

void di_hash_table_destroy ( di_hash_table *  hash_table  ) 

Destroys the di_hash_table. If keys and/or values are dynamically allocated, you should either free them first or create the di_hash_table using di_hash_table_new_full. In the latter case the destroy functions you supplied will be called on all keys and values before destroying the di_hash_table.

Parameters:
hash_table a di_hash_table.

References di_free(), key_destroy_func, mem_chunk, nodes, size, and value_destroy_func.

Referenced by di_packages_free(), and di_release_free().

{
  size_t i;

  for (i = 0; i < hash_table->size; i++)
    internal_di_hash_nodes_destroy (hash_table->nodes[i], hash_table->key_destroy_func, hash_table->value_destroy_func);

  di_mem_chunk_destroy (hash_table->mem_chunk);

  di_free (hash_table->nodes);
  di_free (hash_table);
}

void di_hash_table_foreach ( di_hash_table *  hash_table,
di_hfunc *  func,
void *  user_data 
)

Calls the given function for each of the key/value pairs in the di_hash_table. The function is passed the key and value of each pair, and the given user_data parameter.

Postcondition:
The hash table may not be modified while iterating over it (you can't add/remove items).
Parameters:
hash_table a di_hash_table.
func the function to call for each key/value pair.
user_data user data to pass to the function.

References di_hash_node::key, di_hash_node::next, nodes, size, and di_hash_node::value.

{
  di_hash_node *node;
  size_t i;

  for (i = 0; i < hash_table->size; i++)
    for (node = hash_table->nodes[i]; node; node = node->next)
      func (node->key, node->value, user_data);
}

void di_hash_table_insert ( di_hash_table *  hash_table,
void *  key,
void *  value 
)

Inserts a new key and value into a di_hash_table.

If the key already exists in the di_hash_table its current value is replaced with the new value. If you supplied a value_destroy_func when creating the di_hash_table, the old value is freed using that function. If you supplied a key_destroy_func when creating the di_hash_table, the passed key is freed using that function.

Parameters:
hash_table a di_hash_table.
key a key to insert.
value the value to associate with the key.

References HASH_TABLE_RESIZE, key_destroy_func, nnodes, and value_destroy_func.

Referenced by di_packages_append_package(), and di_packages_get_package_new().

{
  di_hash_node **node;

  node = internal_di_hash_table_lookup_node (hash_table, key);

  if (*node)
  {
    if (hash_table->key_destroy_func)
      hash_table->key_destroy_func (key);

    if (hash_table->value_destroy_func)
      hash_table->value_destroy_func ((*node)->value);

    (*node)->value = value;
  }
  else
  {
    *node = internal_di_hash_node_new (hash_table, key, value);
    hash_table->nnodes++;
    HASH_TABLE_RESIZE (hash_table);
  }
}

void* di_hash_table_lookup ( di_hash_table *  hash_table,
const void *  key 
)

Looks up a key in a di_hash_table.

Parameters:
hash_table a di_hash_table,
key the key to look up.
Returns:
the associated value, or NULL if the key is not found.

References di_hash_node::value.

Referenced by di_packages_get_package(), and di_parser_rfc822_read().

{
  di_hash_node *node;

  node = *internal_di_hash_table_lookup_node (hash_table, key);

  return node ? node->value : NULL;
}

di_hash_table* di_hash_table_new ( di_hash_func  hash_func,
di_equal_func  key_equal_func 
)

Creates a new di_hash_table.

Parameters:
hash_func a function to create a hash value from a key. Hash values are used to determine where keys are stored within the di_hash_table data structure.
key_equal_func a function to check two keys for equality. This is used when looking up keys in the di_hash_table.
Returns:
a new di_hash_table.

References di_hash_table_new_full().

{
  return di_hash_table_new_full (hash_func, key_equal_func, NULL, NULL);
}

di_hash_table* di_hash_table_new_full ( di_hash_func  hash_func,
di_equal_func  key_equal_func,
di_destroy_notify  key_destroy_func,
di_destroy_notify  value_destroy_func 
)

Creates a new di_hash_table like di_hash_table_new and allows to specify functions to free the memory allocated for the key and value that get called when removing the entry from the di_hash_table

Parameters:
hash_func a function to create a hash value from a key. Hash values are used to determine where keys are stored within the di_hash_table data structure.
key_equal_func a function to check two keys for equality. This is used when looking up keys in the di_hash_table.
key_destroy_func a function to free the memory allocated for the key used when removing the entry from the di_hash_table or NULL if you don't want to supply such a function.
value_destroy_func a function to free the memory allocated for the value used when removing the entry from the di_hash_table or NULL if you don't want to supply such a function.
Returns:
a new di_hash_table.

References di_mem_chunk_new(), di_new, hash_func, key_destroy_func, key_equal_func, mem_chunk, nnodes, nodes, size, and value_destroy_func.

Referenced by di_hash_table_new(), di_packages_alloc(), and di_release_alloc().

{
  di_hash_table *hash_table;
  size_t i;

  hash_table = di_new (di_hash_table, 1);
  hash_table->size               = HASH_TABLE_MIN_SIZE;
  hash_table->nnodes             = 0;
  hash_table->mem_chunk          = di_mem_chunk_new (sizeof (di_hash_node), 4096);
  hash_table->hash_func          = hash_func;
  hash_table->key_equal_func     = key_equal_func;
  hash_table->key_destroy_func   = key_destroy_func;
  hash_table->value_destroy_func = value_destroy_func;
  hash_table->nodes              = di_new (di_hash_node*, hash_table->size);

  for (i = 0; i < hash_table->size; i++)
    hash_table->nodes[i] = NULL;

  return hash_table;
}

di_ksize_t di_hash_table_size ( di_hash_table *  hash_table  ) 

Returns the number of elements contained in the di_hash_table.

Parameters:
hash_table a di_hash_table.
Returns:
the number of key/value pairs.

References nnodes.

{
  return hash_table->nnodes;
}

Generated on Tue Jan 10 2012 15:21:37 for libdebian-installer by  doxygen 1.7.1