glib2.0/glib/gbsearcharray.h

300 lines
12 KiB
C

/* GBSearchArray - Binary Searchable Array implementation
* Copyright (C) 2000-2003 Tim Janik
*
* This software is provided "as is"; redistribution and modification
* is permitted, provided that the following disclaimer is retained.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* In no event shall the authors 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.
*/
#ifndef __G_BSEARCH_ARRAY_H__
#define __G_BSEARCH_ARRAY_H__
#include <glib.h>
#include <string.h>
G_BEGIN_DECLS /* c++ guards */
/* this implementation is intended to be usable in third-party code
* simply by pasting the contents of this file. as such, the
* implementation needs to be self-contained within this file.
*/
/* convenience macro to avoid signed overflow for value comparisons */
#define G_BSEARCH_ARRAY_CMP(v1,v2) ((v1) > (v2) ? +1 : (v1) == (v2) ? 0 : -1)
/* --- typedefs --- */
typedef gint (*GBSearchCompareFunc) (gconstpointer bsearch_node1, /* key */
gconstpointer bsearch_node2);
typedef enum
{
G_BSEARCH_ARRAY_ALIGN_POWER2 = 1 << 0, /* align memory to power2 sizes */
G_BSEARCH_ARRAY_AUTO_SHRINK = 1 << 1 /* shrink array upon removal */
} GBSearchArrayFlags;
/* --- structures --- */
typedef struct
{
guint sizeof_node;
GBSearchCompareFunc cmp_nodes;
guint flags;
} GBSearchConfig;
typedef union
{
guint n_nodes;
/*< private >*/
gpointer alignment_dummy1;
glong alignment_dummy2;
gdouble alignment_dummy3;
} GBSearchArray;
/* --- public API --- */
static inline GBSearchArray* g_bsearch_array_create (const GBSearchConfig *bconfig);
static inline gpointer g_bsearch_array_get_nth (GBSearchArray *barray,
const GBSearchConfig *bconfig,
guint nth);
static inline guint g_bsearch_array_get_index (GBSearchArray *barray,
const GBSearchConfig *bconfig,
gconstpointer node_in_array);
static inline GBSearchArray* g_bsearch_array_remove (GBSearchArray *barray,
const GBSearchConfig *bconfig,
guint index_);
/* provide uninitialized space at index for node insertion */
static inline GBSearchArray* g_bsearch_array_grow (GBSearchArray *barray,
const GBSearchConfig *bconfig,
guint index);
/* insert key_node into array if it does not exist, otherwise do nothing */
static inline GBSearchArray* g_bsearch_array_insert (GBSearchArray *barray,
const GBSearchConfig *bconfig,
gconstpointer key_node);
/* insert key_node into array if it does not exist,
* otherwise replace the existing node's contents with key_node
*/
static inline GBSearchArray* g_bsearch_array_replace (GBSearchArray *barray,
const GBSearchConfig *bconfig,
gconstpointer key_node);
static inline void g_bsearch_array_free (GBSearchArray *barray,
const GBSearchConfig *bconfig);
#define g_bsearch_array_get_n_nodes(barray) (((GBSearchArray*) (barray))->n_nodes)
/* g_bsearch_array_lookup():
* return NULL or exact match node
*/
#define g_bsearch_array_lookup(barray, bconfig, key_node) \
g_bsearch_array_lookup_fuzzy ((barray), (bconfig), (key_node), 0)
/* g_bsearch_array_lookup_sibling():
* return NULL for barray->n_nodes==0, otherwise return the
* exact match node, or, if there's no such node, return the
* node last visited, which is pretty close to an exact match
* (will be one off into either direction).
*/
#define g_bsearch_array_lookup_sibling(barray, bconfig, key_node) \
g_bsearch_array_lookup_fuzzy ((barray), (bconfig), (key_node), 1)
/* g_bsearch_array_lookup_insertion():
* return NULL for barray->n_nodes==0 or exact match, otherwise
* return the node where key_node should be inserted (may be one
* after end, i.e. g_bsearch_array_get_index(result) <= barray->n_nodes).
*/
#define g_bsearch_array_lookup_insertion(barray, bconfig, key_node) \
g_bsearch_array_lookup_fuzzy ((barray), (bconfig), (key_node), 2)
/* --- implementation --- */
/* helper macro to cut down realloc()s */
#define G_BSEARCH_UPPER_POWER2(n) ((n) ? 1 << g_bit_storage ((n) - 1) : 0)
#define G_BSEARCH_ARRAY_NODES(barray) (((guint8*) (barray)) + sizeof (GBSearchArray))
static inline GBSearchArray*
g_bsearch_array_create (const GBSearchConfig *bconfig)
{
GBSearchArray *barray;
guint size;
g_return_val_if_fail (bconfig != NULL, NULL);
size = sizeof (GBSearchArray) + bconfig->sizeof_node;
if (bconfig->flags & G_BSEARCH_ARRAY_ALIGN_POWER2)
size = G_BSEARCH_UPPER_POWER2 (size);
barray = (GBSearchArray *) g_malloc (size);
memset (barray, 0, sizeof (GBSearchArray));
return barray;
}
static inline gpointer
g_bsearch_array_lookup_fuzzy (GBSearchArray *barray,
const GBSearchConfig *bconfig,
gconstpointer key_node,
const guint sibling_or_after);
static inline gpointer
g_bsearch_array_lookup_fuzzy (GBSearchArray *barray,
const GBSearchConfig *bconfig,
gconstpointer key_node,
const guint sibling_or_after)
{
GBSearchCompareFunc cmp_nodes = bconfig->cmp_nodes;
guint8 *check = NULL, *nodes = G_BSEARCH_ARRAY_NODES (barray);
guint n_nodes = barray->n_nodes, offs = 0;
guint sizeof_node = bconfig->sizeof_node;
gint cmp = 0;
while (offs < n_nodes)
{
guint i = (offs + n_nodes) >> 1;
check = nodes + i * sizeof_node;
cmp = cmp_nodes (key_node, check);
if (cmp == 0)
return sibling_or_after > 1 ? NULL : check;
else if (cmp < 0)
n_nodes = i;
else /* (cmp > 0) */
offs = i + 1;
}
/* check is last mismatch, cmp > 0 indicates greater key */
return G_LIKELY (!sibling_or_after) ? NULL : (sibling_or_after > 1 && cmp > 0) ? check + sizeof_node : check;
}
static inline gpointer
g_bsearch_array_get_nth (GBSearchArray *barray,
const GBSearchConfig *bconfig,
guint nth)
{
return (G_LIKELY (nth < barray->n_nodes) ?
G_BSEARCH_ARRAY_NODES (barray) + nth * bconfig->sizeof_node :
NULL);
}
static inline guint
g_bsearch_array_get_index (GBSearchArray *barray,
const GBSearchConfig *bconfig,
gconstpointer node_in_array)
{
guint distance = ((guint8*) node_in_array) - G_BSEARCH_ARRAY_NODES (barray);
g_return_val_if_fail (node_in_array != NULL, barray->n_nodes);
distance /= bconfig->sizeof_node;
return MIN (distance, barray->n_nodes + 1); /* may return one after end */
}
static inline GBSearchArray*
g_bsearch_array_grow (GBSearchArray *barray,
const GBSearchConfig *bconfig,
guint index_)
{
guint old_size = barray->n_nodes * bconfig->sizeof_node;
guint new_size = old_size + bconfig->sizeof_node;
guint8 *node;
g_return_val_if_fail (index_ <= barray->n_nodes, NULL);
if (G_UNLIKELY (bconfig->flags & G_BSEARCH_ARRAY_ALIGN_POWER2))
{
new_size = G_BSEARCH_UPPER_POWER2 (sizeof (GBSearchArray) + new_size);
old_size = G_BSEARCH_UPPER_POWER2 (sizeof (GBSearchArray) + old_size);
if (old_size != new_size)
barray = (GBSearchArray *) g_realloc (barray, new_size);
}
else
barray = (GBSearchArray *) g_realloc (barray, sizeof (GBSearchArray) + new_size);
node = G_BSEARCH_ARRAY_NODES (barray) + index_ * bconfig->sizeof_node;
memmove (node + bconfig->sizeof_node, node, (barray->n_nodes - index_) * bconfig->sizeof_node);
barray->n_nodes += 1;
return barray;
}
static inline GBSearchArray*
g_bsearch_array_insert (GBSearchArray *barray,
const GBSearchConfig *bconfig,
gconstpointer key_node)
{
guint8 *node;
if (G_UNLIKELY (!barray->n_nodes))
{
barray = g_bsearch_array_grow (barray, bconfig, 0);
node = G_BSEARCH_ARRAY_NODES (barray);
}
else
{
node = (guint8 *) g_bsearch_array_lookup_insertion (barray, bconfig, key_node);
if (G_LIKELY (node))
{
guint index_ = g_bsearch_array_get_index (barray, bconfig, node);
/* grow and insert */
barray = g_bsearch_array_grow (barray, bconfig, index_);
node = G_BSEARCH_ARRAY_NODES (barray) + index_ * bconfig->sizeof_node;
}
else /* no insertion needed, node already there */
return barray;
}
memcpy (node, key_node, bconfig->sizeof_node);
return barray;
}
static inline GBSearchArray*
g_bsearch_array_replace (GBSearchArray *barray,
const GBSearchConfig *bconfig,
gconstpointer key_node)
{
guint8 *node = (guint8 *) g_bsearch_array_lookup (barray, bconfig, key_node);
if (G_LIKELY (node)) /* expected path */
memcpy (node, key_node, bconfig->sizeof_node);
else /* revert to insertion */
barray = g_bsearch_array_insert (barray, bconfig, key_node);
return barray;
}
static inline GBSearchArray*
g_bsearch_array_remove (GBSearchArray *barray,
const GBSearchConfig *bconfig,
guint index_)
{
guint8 *node;
g_return_val_if_fail (index_ < barray->n_nodes, NULL);
barray->n_nodes -= 1;
node = G_BSEARCH_ARRAY_NODES (barray) + index_ * bconfig->sizeof_node;
memmove (node, node + bconfig->sizeof_node, (barray->n_nodes - index_) * bconfig->sizeof_node);
if (G_UNLIKELY (bconfig->flags & G_BSEARCH_ARRAY_AUTO_SHRINK))
{
guint new_size = barray->n_nodes * bconfig->sizeof_node;
guint old_size = new_size + bconfig->sizeof_node;
if (G_UNLIKELY (bconfig->flags & G_BSEARCH_ARRAY_ALIGN_POWER2))
{
new_size = G_BSEARCH_UPPER_POWER2 (sizeof (GBSearchArray) + new_size);
old_size = G_BSEARCH_UPPER_POWER2 (sizeof (GBSearchArray) + old_size);
if (old_size != new_size)
barray = (GBSearchArray *) g_realloc (barray, new_size);
}
else
barray = (GBSearchArray *) g_realloc (barray, sizeof (GBSearchArray) + new_size);
}
return barray;
}
static inline void
g_bsearch_array_free (GBSearchArray *barray,
const GBSearchConfig *bconfig)
{
g_return_if_fail (barray != NULL);
g_free (barray);
}
G_END_DECLS /* c++ guards */
#endif /* !__G_BSEARCH_ARRAY_H__ */