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Bob Halley
1998-10-15 23:51:14 +00:00
parent 7bae6a079b
commit 00c6365ade
1 changed files with 53 additions and 57 deletions
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110
lib/isc/heap.c
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@@ -25,10 +25,6 @@
* ISBN 0-201-06673-4, chapter 11.
*/
#if !defined(LINT) && !defined(CODECENTER)
static char rcsid[] = "$Id: heap.c,v 1.1 1998/10/15 23:42:56 halley Exp $";
#endif /* not lint */
#include <stdlib.h>
#include <isc/assertions.h>
@@ -40,10 +36,10 @@ static char rcsid[] = "$Id: heap.c,v 1.1 1998/10/15 23:42:56 halley Exp $";
* element of the heap array is not used; i.e. heap subscripts are 1-based,
* not 0-based.
*/
#define heap_parent(i) ((i) >> 1)
#define heap_left(i) ((i) << 1)
#define heap_parent(i) ((i) >> 1)
#define heap_left(i) ((i) << 1)
#define ARRAY_SIZE_INCREMENT 512
#define SIZE_INCREMENT 1024
#define HEAP_MAGIC 0x48454150U /* HEAP. */
#define VALID_CONTEXT(ctx) ((ctx) != NULL && \
@@ -52,17 +48,17 @@ static char rcsid[] = "$Id: heap.c,v 1.1 1998/10/15 23:42:56 halley Exp $";
struct heap_context {
unsigned int magic;
mem_context_t mctx;
unsigned int array_size;
unsigned int array_size_increment;
unsigned int heap_size;
void **heap;
unsigned int size;
unsigned int size_increment;
unsigned int last;
void **array;
heap_higher_priority_func higher_priority;
heap_index_func index;
};
isc_result
heap_create(mem_context_t mctx, heap_higher_priority_func higher_priority,
heap_index_func index, unsigned int array_size_increment,
heap_index_func index, unsigned int size_increment,
heap_context_t *ctxp)
{
heap_context_t ctx;
@@ -74,13 +70,13 @@ heap_create(mem_context_t mctx, heap_higher_priority_func higher_priority,
if (ctx == NULL)
return (ISC_R_NOMEMORY);
ctx->magic = HEAP_MAGIC;
ctx->array_size = 0;
if (array_size_increment == 0)
ctx->array_size_increment = ARRAY_SIZE_INCREMENT;
ctx->size = 0;
if (size_increment == 0)
ctx->size_increment = SIZE_INCREMENT;
else
ctx->array_size_increment = array_size_increment;
ctx->heap_size = 0;
ctx->heap = NULL;
ctx->size_increment = size_increment;
ctx->last = 0;
ctx->array = NULL;
ctx->higher_priority = higher_priority;
ctx->index = index;
@@ -97,9 +93,9 @@ heap_destroy(heap_context_t *ctxp) {
ctx = *ctxp;
REQUIRE(VALID_CONTEXT(ctx));
if (ctx->heap != NULL)
mem_put(ctx->mctx, ctx->heap,
ctx->array_size * sizeof (void *));
if (ctx->array != NULL)
mem_put(ctx->mctx, ctx->array,
ctx->size * sizeof (void *));
ctx->magic = 0;
mem_put(ctx->mctx, ctx, sizeof *ctx);
@@ -107,21 +103,21 @@ heap_destroy(heap_context_t *ctxp) {
}
static boolean_t
heap_resize(heap_context_t ctx) {
void **new_heap;
resize(heap_context_t ctx) {
void **new_array;
size_t new_size;
REQUIRE(VALID_CONTEXT(ctx));
new_size = ctx->array_size + ctx->array_size_increment;
new_heap = mem_get(ctx->mctx, new_size * sizeof (void *));
if (new_heap == NULL)
new_size = ctx->size + ctx->size_increment;
new_array = mem_get(ctx->mctx, new_size * sizeof (void *));
if (new_array == NULL)
return (FALSE);
memcpy(new_heap, ctx->heap, ctx->array_size);
mem_put(ctx->mctx, ctx->heap,
ctx->array_size * sizeof (void *));
ctx->array_size = new_size;
ctx->heap = new_heap;
memcpy(new_array, ctx->array, ctx->size);
mem_put(ctx->mctx, ctx->array,
ctx->size * sizeof (void *));
ctx->size = new_size;
ctx->array = new_array;
return (TRUE);
}
@@ -131,39 +127,39 @@ float_up(heap_context_t ctx, unsigned int i, void *elt) {
unsigned int p;
for ( p = heap_parent(i);
i > 1 && ctx->higher_priority(elt, ctx->heap[p]);
i > 1 && ctx->higher_priority(elt, ctx->array[p]);
i = p, p = heap_parent(i) ) {
ctx->heap[i] = ctx->heap[p];
ctx->array[i] = ctx->array[p];
if (ctx->index != NULL)
(ctx->index)(ctx->heap[i], i);
(ctx->index)(ctx->array[i], i);
}
ctx->heap[i] = elt;
ctx->array[i] = elt;
if (ctx->index != NULL)
(ctx->index)(ctx->heap[i], i);
(ctx->index)(ctx->array[i], i);
}
static void
sink_down(heap_context_t ctx, unsigned int i, void *elt) {
unsigned int j, size, half_size;
size = ctx->heap_size;
size = ctx->last;
half_size = size / 2;
while (i <= half_size) {
/* find smallest of the (at most) two children */
j = heap_left(i);
if (j < size && ctx->higher_priority(ctx->heap[j+1],
ctx->heap[j]))
if (j < size && ctx->higher_priority(ctx->array[j+1],
ctx->array[j]))
j++;
if (ctx->higher_priority(elt, ctx->heap[j]))
if (ctx->higher_priority(elt, ctx->array[j]))
break;
ctx->heap[i] = ctx->heap[j];
ctx->array[i] = ctx->array[j];
if (ctx->index != NULL)
(ctx->index)(ctx->heap[i], i);
(ctx->index)(ctx->array[i], i);
i = j;
}
ctx->heap[i] = elt;
ctx->array[i] = elt;
if (ctx->index != NULL)
(ctx->index)(ctx->heap[i], i);
(ctx->index)(ctx->array[i], i);
}
isc_result
@@ -172,8 +168,8 @@ heap_insert(heap_context_t ctx, void *elt) {
REQUIRE(VALID_CONTEXT(ctx));
i = ++ctx->heap_size;
if (ctx->heap_size >= ctx->array_size && !heap_resize(ctx))
i = ++ctx->last;
if (ctx->last >= ctx->size && !resize(ctx))
return (ISC_R_NOMEMORY);
float_up(ctx, i, elt);
@@ -186,35 +182,35 @@ heap_delete(heap_context_t ctx, unsigned int i) {
void *elt;
REQUIRE(VALID_CONTEXT(ctx));
REQUIRE(i >= 1 && i <= ctx->heap_size);
REQUIRE(i >= 1 && i <= ctx->last);
elt = ctx->heap[ctx->heap_size];
if (--ctx->heap_size > 0)
elt = ctx->array[ctx->last];
if (--ctx->last > 0)
sink_down(ctx, i, elt);
}
void
heap_increased(heap_context_t ctx, unsigned int i) {
REQUIRE(VALID_CONTEXT(ctx));
REQUIRE(i >= 1 && i <= ctx->heap_size);
REQUIRE(i >= 1 && i <= ctx->last);
float_up(ctx, i, ctx->heap[i]);
float_up(ctx, i, ctx->array[i]);
}
void
heap_decreased(heap_context_t ctx, unsigned int i) {
REQUIRE(VALID_CONTEXT(ctx));
REQUIRE(i >= 1 && i <= ctx->heap_size);
REQUIRE(i >= 1 && i <= ctx->last);
sink_down(ctx, i, ctx->heap[i]);
sink_down(ctx, i, ctx->array[i]);
}
void *
heap_element(heap_context_t ctx, unsigned int i) {
REQUIRE(VALID_CONTEXT(ctx));
REQUIRE(i >= 1 && i <= ctx->heap_size);
REQUIRE(i >= 1 && i <= ctx->last);
return (ctx->heap[i]);
return (ctx->array[i]);
}
void
@@ -224,6 +220,6 @@ heap_for_each(heap_context_t ctx, heap_for_each_func action, void *uap) {
REQUIRE(VALID_CONTEXT(ctx));
REQUIRE(action != NULL);
for (i = 1; i <= ctx->heap_size; i++)
(action)(ctx->heap[i], uap);
for (i = 1; i <= ctx->last; i++)
(action)(ctx->array[i], uap);
}