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/*************************************************************************
* Copyright (C) 2010 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension Library is free software; you can redistribute it and/ *
* or modify it under the terms of the GNU Lesser General Public License *
* as published by the Free Software Foundation; either version 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension Library 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. See the GNU *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
/**
* @file
* Generic maps.
*/
#include "dimension.h"
#include <alloca.h>
/** An [index, object] pair. */
typedef struct dmnsn_map_entry {
double n;
char object[];
} dmnsn_map_entry;
dmnsn_map *
dmnsn_new_map(size_t size)
{
dmnsn_map *map = dmnsn_malloc(sizeof(dmnsn_map));
map->free_fn = NULL;
map->obj_size = size;
map->array = dmnsn_new_array(sizeof(dmnsn_map_entry) + size);
return map;
}
void
dmnsn_delete_map(dmnsn_map *map)
{
if (map) {
if (map->free_fn) {
for (size_t i = 0; i < dmnsn_array_size(map->array); ++i) {
dmnsn_map_entry *entry = dmnsn_array_at(map->array, i);
(*map->free_fn)(entry->object);
}
}
dmnsn_delete_array(map->array);
dmnsn_free(map);
}
}
void
dmnsn_add_map_entry(dmnsn_map *map, double n, const void *obj)
{
dmnsn_map_entry *entry = alloca(sizeof(dmnsn_map_entry) + map->obj_size);
entry->n = n;
memcpy(entry->object, obj, map->obj_size);
/* Sorted insertion */
size_t i;
for (i = dmnsn_array_size(map->array); i-- > 0;) {
dmnsn_map_entry *other = dmnsn_array_at(map->array, i);
if (other->n <= n)
break;
}
dmnsn_array_insert(map->array, i + 1, entry);
}
size_t
dmnsn_map_size(const dmnsn_map *map)
{
return dmnsn_array_size(map->array);
}
void
dmnsn_evaluate_map(const dmnsn_map *map, double n,
double *val, void *obj1, void *obj2)
{
dmnsn_assert(dmnsn_array_size(map->array) > 0,
"Attempt to evaluate empty map.");
const dmnsn_map_entry *entry = dmnsn_array_first(map->array);
double n1, n2 = 0.0;
const void *o1, *o2 = entry->object;
if (n < n2) {
*val = 0.0;
memcpy(obj1, o2, map->obj_size);
memcpy(obj2, o2, map->obj_size);
return;
}
const dmnsn_map_entry *last = dmnsn_array_last(map->array);
ptrdiff_t skip = sizeof(dmnsn_map_entry) + map->obj_size;
for (; entry <= last;
entry = (const dmnsn_map_entry *)((const char *)entry + skip))
{
n1 = n2;
o1 = o2;
n2 = entry->n;
o2 = entry->object;
if (n < n2) {
*val = (n - n1)/(n2 - n1);
memcpy(obj1, o1, map->obj_size);
memcpy(obj2, o2, map->obj_size);
return;
}
}
*val = 1.0;
memcpy(obj1, o2, map->obj_size);
memcpy(obj2, o2, map->obj_size);
}
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