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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Authors: Rickard E. (Rik) Faith <faith@valinux.com>
*
* DESCRIPTION
*
* This file contains a straightforward skip list implementation.n
*
* FUTURE ENHANCEMENTS
*
* REFERENCES
*
* [Pugh90] William Pugh. Skip Lists: A Probabilistic Alternative to
* Balanced Trees. CACM 33(6), June 1990, pp. 668-676.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include "xf86drm.h"
static void print(void* list)
{
unsigned long key;
void *value;
if (drmSLFirst(list, &key, &value)) {
do {
printf("key = %5lu, value = %p\n", key, value);
} while (drmSLNext(list, &key, &value));
}
}
static double do_time(int size, int iter)
{
void *list;
int i, j;
unsigned long keys[1000000];
unsigned long previous;
unsigned long key;
void *value;
struct timeval start, stop;
double usec;
void *ranstate;
list = drmSLCreate();
ranstate = drmRandomCreate(12345);
for (i = 0; i < size; i++) {
keys[i] = drmRandom(ranstate);
drmSLInsert(list, keys[i], NULL);
}
previous = 0;
if (drmSLFirst(list, &key, &value)) {
do {
if (key <= previous) {
printf( "%lu !< %lu\n", previous, key);
}
previous = key;
} while (drmSLNext(list, &key, &value));
}
gettimeofday(&start, NULL);
for (j = 0; j < iter; j++) {
for (i = 0; i < size; i++) {
if (drmSLLookup(list, keys[i], &value))
printf("Error %lu %d\n", keys[i], i);
}
}
gettimeofday(&stop, NULL);
usec = (double)(stop.tv_sec * 1000000 + stop.tv_usec
- start.tv_sec * 1000000 - start.tv_usec) / (size * iter);
printf("%0.2f microseconds for list length %d\n", usec, size);
drmRandomDouble(ranstate);
drmSLDestroy(list);
return usec;
}
static void print_neighbors(void *list, unsigned long key)
{
unsigned long prev_key = 0;
unsigned long next_key = 0;
void *prev_value;
void *next_value;
int retval;
retval = drmSLLookupNeighbors(list, key,
&prev_key, &prev_value,
&next_key, &next_value);
printf("Neighbors of %5lu: %d %5lu %5lu\n",
key, retval, prev_key, next_key);
}
int main(void)
{
void* list;
double usec, usec2, usec3, usec4;
list = drmSLCreate();
printf( "list at %p\n", list);
print(list);
printf("\n==============================\n\n");
drmSLInsert(list, 123, NULL);
drmSLInsert(list, 213, NULL);
drmSLInsert(list, 50, NULL);
print(list);
printf("\n==============================\n\n");
print_neighbors(list, 0);
print_neighbors(list, 50);
print_neighbors(list, 51);
print_neighbors(list, 123);
print_neighbors(list, 200);
print_neighbors(list, 213);
print_neighbors(list, 256);
printf("\n==============================\n\n");
drmSLDelete(list, 50);
print(list);
printf("\n==============================\n\n");
drmSLDump(list);
drmSLDestroy(list);
printf("\n==============================\n\n");
usec = do_time(100, 10000);
usec2 = do_time(1000, 500);
printf("Table size increased by %0.2f, search time increased by %0.2f\n",
1000.0/100.0, usec2 / usec);
usec3 = do_time(10000, 50);
printf("Table size increased by %0.2f, search time increased by %0.2f\n",
10000.0/100.0, usec3 / usec);
usec4 = do_time(100000, 4);
printf("Table size increased by %0.2f, search time increased by %0.2f\n",
100000.0/100.0, usec4 / usec);
return 0;
}
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