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add threshold search operation to 'oset' modules
From: |
Bruno Haible |
Subject: |
add threshold search operation to 'oset' modules |
Date: |
Wed, 4 Oct 2006 19:23:52 +0200 |
User-agent: |
KMail/1.9.1 |
Hi,
The ordered set datatype is missing an operation: search of the least
element >= a given threshold. I'm adding it, since the 'list' modules will
need it.
2006-10-03 Bruno Haible <address@hidden>
* gl_oset.h (gl_setelement_threshold_fn): New type.
(gl_oset_search_atleast): New declaration.
(struct gl_oset_implementation): Add field 'search_atleast'.
(gl_oset_search_atleast): New inline function.
* gl_oset.c (gl_oset_search_atleast): New function.
* gl_array_oset.c (gl_array_search_atleast): New function.
(gl_array_oset_implementation): Update.
* gl_anytree_oset.h (gl_tree_search_atleast): New function.
* gl_avltree_oset.c (gl_avltree_oset_implementation): Update.
* gl_rbtree_oset.c (gl_rbtree_oset_implementation): Update.
*** gnulib-20060928/lib/gl_oset.h 2006-07-18 03:15:00.000000000 +0200
--- gnulib-20060928-modified/lib/gl_oset.h 2006-10-03 19:28:54.000000000
+0200
***************
*** 59,64 ****
--- 59,65 ----
gl_oset_add O(n) O(log n)
gl_oset_remove O(n) O(log n)
gl_oset_search O(log n) O(log n)
+ gl_oset_search_atleast O(log n) O(log n)
gl_oset_iterator O(1) O(log n)
gl_oset_iterator_next O(1) O(log n)
*/
***************
*** 69,74 ****
--- 70,79 ----
NULL denotes pointer comparison. */
typedef int (*gl_setelement_compar_fn) (const void *elt1, const void *elt2);
+ /* Type of function used to compare an element with a threshold.
+ Return true if the element is greater or equal than the threshold. */
+ typedef bool (*gl_setelement_threshold_fn) (const void *elt, const void
*threshold);
+
struct gl_oset_impl;
/* Type representing an entire ordered set. */
typedef struct gl_oset_impl * gl_oset_t;
***************
*** 90,95 ****
--- 95,110 ----
Return true if found, or false if not present in the set. */
extern bool gl_oset_search (gl_oset_t set, const void *elt);
+ /* Search the least element in the ordered set that compares greater or equal
+ to the given THRESHOLD. The representation of the THRESHOLD is defined
+ by the THRESHOLD_FN.
+ Return true and store the found element in *ELTP if found, otherwise return
+ false. */
+ extern bool gl_oset_search_atleast (gl_oset_t set,
+ gl_setelement_threshold_fn threshold_fn,
+ const void *threshold,
+ const void **eltp);
+
/* Add an element to an ordered set.
Return true if it was not already in the set and added. */
extern bool gl_oset_add (gl_oset_t set, const void *elt);
***************
*** 143,148 ****
--- 158,166 ----
gl_setelement_compar_fn compar_fn);
size_t (*size) (gl_oset_t set);
bool (*search) (gl_oset_t set, const void *elt);
+ bool (*search_atleast) (gl_oset_t set,
+ gl_setelement_threshold_fn threshold_fn,
+ const void *threshold, const void **eltp);
bool (*add) (gl_oset_t set, const void *elt);
bool (*remove) (gl_oset_t set, const void *elt);
void (*oset_free) (gl_oset_t set);
***************
*** 186,191 ****
--- 204,219 ----
return ((const struct gl_oset_impl_base *) set)->vtable->search (set, elt);
}
+ # define gl_oset_search_atleast gl_oset_search_atleast_inline
+ static inline bool
+ gl_oset_search_atleast (gl_oset_t set,
+ gl_setelement_threshold_fn threshold_fn,
+ const void *threshold, const void **eltp)
+ {
+ return ((const struct gl_oset_impl_base *) set)->vtable
+ ->search_atleast (set, threshold_fn, threshold, eltp);
+ }
+
# define gl_oset_add gl_oset_add_inline
static inline bool
gl_oset_add (gl_oset_t set, const void *elt)
*** gnulib-20060928/lib/gl_oset.c 2006-10-03 19:41:35.000000000 +0200
--- gnulib-20060928-modified/lib/gl_oset.c 2006-10-03 19:29:40.000000000
+0200
***************
*** 47,52 ****
--- 47,61 ----
}
bool
+ gl_oset_search_atleast (gl_oset_t set,
+ gl_setelement_threshold_fn threshold_fn,
+ const void *threshold, const void **eltp)
+ {
+ return ((const struct gl_oset_impl_base *) set)->vtable
+ ->search_atleast (set, threshold_fn, threshold, eltp);
+ }
+
+ bool
gl_oset_add (gl_oset_t set, const void *elt)
{
return ((const struct gl_oset_impl_base *) set)->vtable->add (set, elt);
*** gnulib-20060928/lib/gl_array_oset.c 2006-10-03 19:21:05.000000000 +0200
--- gnulib-20060928-modified/lib/gl_array_oset.c 2006-10-03
19:33:52.000000000 +0200
***************
*** 105,110 ****
--- 105,160 ----
return gl_array_indexof (set, elt) != (size_t)(-1);
}
+ static bool
+ gl_array_search_atleast (gl_oset_t set,
+ gl_setelement_threshold_fn threshold_fn,
+ const void *threshold,
+ const void **eltp)
+ {
+ size_t count = set->count;
+
+ if (count > 0)
+ {
+ size_t low = 0;
+ size_t high = count;
+
+ /* At each loop iteration, low < high; for indices < low the values are
+ smaller than THRESHOLD; for indices >= high the values are nonexistent.
+ So, if an element >= THRESHOLD occurs in the list, it is at
+ low <= position < high. */
+ do
+ {
+ size_t mid = low + (high - low) / 2; /* low <= mid < high */
+
+ if (! threshold_fn (set->elements[mid], threshold))
+ low = mid + 1;
+ else
+ {
+ /* We have an element >= THRESHOLD at index MID. But we need the
+ minimal such index. */
+ high = mid;
+ /* At each loop iteration, low <= high and
+ compar (list->elements[high], value) >= 0,
+ and we know that the first occurrence of the element is at
+ low <= position <= high. */
+ while (low < high)
+ {
+ size_t mid2 = low + (high - low) / 2; /* low <= mid2 < high */
+
+ if (! threshold_fn (set->elements[mid2], threshold))
+ low = mid2 + 1;
+ else
+ high = mid2;
+ }
+ *eltp = set->elements[low];
+ return true;
+ }
+ }
+ while (low < high);
+ }
+ return false;
+ }
+
/* Ensure that set->allocated > set->count. */
static void
grow (gl_oset_t set)
***************
*** 273,278 ****
--- 323,329 ----
gl_array_create_empty,
gl_array_size,
gl_array_search,
+ gl_array_search_atleast,
gl_array_add,
gl_array_remove,
gl_array_free,
*** gnulib-20060928/lib/gl_anytree_oset.h 2006-09-29 01:08:24.000000000
+0200
--- gnulib-20060928-modified/lib/gl_anytree_oset.h 2006-10-03
19:35:41.000000000 +0200
***************
*** 73,78 ****
--- 73,113 ----
return false;
}
+ static bool
+ gl_tree_search_atleast (gl_oset_t set,
+ gl_setelement_threshold_fn threshold_fn,
+ const void *threshold,
+ const void **eltp)
+ {
+ gl_oset_node_t node;
+
+ for (node = set->root; node != NULL; )
+ {
+ if (! threshold_fn (node->value, threshold))
+ node = node->right;
+ else
+ {
+ /* We have an element >= VALUE. But we need the leftmost such
+ element. */
+ gl_oset_node_t found = node;
+ node = node->left;
+ for (; node != NULL; )
+ {
+ if (! threshold_fn (node->value, threshold))
+ node = node->right;
+ else
+ {
+ found = node;
+ node = node->left;
+ }
+ }
+ *eltp = found;
+ return true;
+ }
+ }
+ return false;
+ }
+
static gl_oset_node_t
gl_tree_search_node (gl_oset_t set, const void *elt)
{
*** gnulib-20060928/lib/gl_avltree_oset.c 2006-09-19 00:51:16.000000000
+0200
--- gnulib-20060928-modified/lib/gl_avltree_oset.c 2006-10-03
18:58:30.000000000 +0200
***************
*** 565,570 ****
--- 565,571 ----
gl_tree_create_empty,
gl_tree_size,
gl_tree_search,
+ gl_tree_search_atleast,
gl_tree_add,
gl_tree_remove,
gl_tree_oset_free,
*** gnulib-20060928/lib/gl_rbtree_oset.c 2006-09-19 00:51:16.000000000
+0200
--- gnulib-20060928-modified/lib/gl_rbtree_oset.c 2006-10-03
18:58:42.000000000 +0200
***************
*** 796,801 ****
--- 796,802 ----
gl_tree_create_empty,
gl_tree_size,
gl_tree_search,
+ gl_tree_search_atleast,
gl_tree_add,
gl_tree_remove,
gl_tree_oset_free,
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