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