cc283d3c86
Now that xenocara has been made clean with respect to using kernel headers instead of those provided with libdrm, remove the copy of the headers included here. Since it is now very simple, move it over to using standard bsd makefiles instead of autoconf. ok matthieu@
481 lines
12 KiB
C
481 lines
12 KiB
C
/* xf86drmSL.c -- Skip list support
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* Created: Mon May 10 09:28:13 1999 by faith@precisioninsight.com
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*
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* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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* Authors: Rickard E. (Rik) Faith <faith@valinux.com>
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*
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* DESCRIPTION
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*
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* This file contains a straightforward skip list implementation.n
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*
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* FUTURE ENHANCEMENTS
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*
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* REFERENCES
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*
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* [Pugh90] William Pugh. Skip Lists: A Probabilistic Alternative to
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* Balanced Trees. CACM 33(6), June 1990, pp. 668-676.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#define SL_MAIN 0
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#if !SL_MAIN
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# include "xf86drm.h"
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#else
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# include <sys/time.h>
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#endif
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#define SL_LIST_MAGIC 0xfacade00LU
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#define SL_ENTRY_MAGIC 0x00fab1edLU
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#define SL_FREED_MAGIC 0xdecea5edLU
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#define SL_MAX_LEVEL 16
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#define SL_DEBUG 0
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#define SL_RANDOM_SEED 0xc01055a1LU
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#if SL_MAIN
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#define SL_ALLOC malloc
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#define SL_FREE free
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#define SL_RANDOM_DECL static int state = 0;
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#define SL_RANDOM_INIT(seed) if (!state) { srandom(seed); ++state; }
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#define SL_RANDOM random()
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#else
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#define SL_ALLOC drmMalloc
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#define SL_FREE drmFree
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#define SL_RANDOM_DECL static void *state = NULL
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#define SL_RANDOM_INIT(seed) if (!state) state = drmRandomCreate(seed)
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#define SL_RANDOM drmRandom(state)
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#endif
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typedef struct SLEntry {
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unsigned long magic; /* SL_ENTRY_MAGIC */
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unsigned long key;
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void *value;
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int levels;
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struct SLEntry *forward[1]; /* variable sized array */
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} SLEntry, *SLEntryPtr;
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typedef struct SkipList {
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unsigned long magic; /* SL_LIST_MAGIC */
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int level;
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int count;
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SLEntryPtr head;
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SLEntryPtr p0; /* Position for iteration */
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} SkipList, *SkipListPtr;
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#if SL_MAIN
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extern void *drmSLCreate(void);
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extern int drmSLDestroy(void *l);
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extern int drmSLLookup(void *l, unsigned long key, void **value);
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extern int drmSLInsert(void *l, unsigned long key, void *value);
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extern int drmSLDelete(void *l, unsigned long key);
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extern int drmSLNext(void *l, unsigned long *key, void **value);
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extern int drmSLFirst(void *l, unsigned long *key, void **value);
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extern void drmSLDump(void *l);
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extern int drmSLLookupNeighbors(void *l, unsigned long key,
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unsigned long *prev_key, void **prev_value,
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unsigned long *next_key, void **next_value);
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#endif
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static SLEntryPtr SLCreateEntry(int max_level, unsigned long key, void *value)
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{
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SLEntryPtr entry;
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if (max_level < 0 || max_level > SL_MAX_LEVEL) max_level = SL_MAX_LEVEL;
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entry = SL_ALLOC(sizeof(*entry)
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+ (max_level + 1) * sizeof(entry->forward[0]));
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if (!entry) return NULL;
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entry->magic = SL_ENTRY_MAGIC;
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entry->key = key;
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entry->value = value;
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entry->levels = max_level + 1;
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return entry;
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}
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static int SLRandomLevel(void)
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{
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int level = 1;
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SL_RANDOM_DECL;
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SL_RANDOM_INIT(SL_RANDOM_SEED);
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while ((SL_RANDOM & 0x01) && level < SL_MAX_LEVEL) ++level;
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return level;
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}
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void *drmSLCreate(void)
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{
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SkipListPtr list;
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int i;
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list = SL_ALLOC(sizeof(*list));
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if (!list) return NULL;
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list->magic = SL_LIST_MAGIC;
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list->level = 0;
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list->head = SLCreateEntry(SL_MAX_LEVEL, 0, NULL);
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list->count = 0;
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for (i = 0; i <= SL_MAX_LEVEL; i++) list->head->forward[i] = NULL;
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return list;
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}
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int drmSLDestroy(void *l)
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{
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SkipListPtr list = (SkipListPtr)l;
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SLEntryPtr entry;
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SLEntryPtr next;
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if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */
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for (entry = list->head; entry; entry = next) {
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if (entry->magic != SL_ENTRY_MAGIC) return -1; /* Bad magic */
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next = entry->forward[0];
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entry->magic = SL_FREED_MAGIC;
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SL_FREE(entry);
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}
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list->magic = SL_FREED_MAGIC;
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SL_FREE(list);
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return 0;
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}
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static SLEntryPtr SLLocate(void *l, unsigned long key, SLEntryPtr *update)
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{
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SkipListPtr list = (SkipListPtr)l;
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SLEntryPtr entry;
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int i;
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if (list->magic != SL_LIST_MAGIC) return NULL;
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for (i = list->level, entry = list->head; i >= 0; i--) {
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while (entry->forward[i] && entry->forward[i]->key < key)
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entry = entry->forward[i];
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update[i] = entry;
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}
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return entry->forward[0];
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}
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int drmSLInsert(void *l, unsigned long key, void *value)
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{
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SkipListPtr list = (SkipListPtr)l;
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SLEntryPtr entry;
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SLEntryPtr update[SL_MAX_LEVEL + 1];
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int level;
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int i;
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if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */
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entry = SLLocate(list, key, update);
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if (entry && entry->key == key) return 1; /* Already in list */
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level = SLRandomLevel();
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if (level > list->level) {
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level = ++list->level;
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update[level] = list->head;
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}
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entry = SLCreateEntry(level, key, value);
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/* Fix up forward pointers */
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for (i = 0; i <= level; i++) {
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entry->forward[i] = update[i]->forward[i];
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update[i]->forward[i] = entry;
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}
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++list->count;
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return 0; /* Added to table */
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}
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int drmSLDelete(void *l, unsigned long key)
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{
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SkipListPtr list = (SkipListPtr)l;
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SLEntryPtr update[SL_MAX_LEVEL + 1];
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SLEntryPtr entry;
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int i;
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if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */
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entry = SLLocate(list, key, update);
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if (!entry || entry->key != key) return 1; /* Not found */
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/* Fix up forward pointers */
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for (i = 0; i <= list->level; i++) {
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if (update[i]->forward[i] == entry)
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update[i]->forward[i] = entry->forward[i];
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}
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entry->magic = SL_FREED_MAGIC;
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SL_FREE(entry);
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while (list->level && !list->head->forward[list->level]) --list->level;
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--list->count;
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return 0;
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}
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int drmSLLookup(void *l, unsigned long key, void **value)
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{
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SkipListPtr list = (SkipListPtr)l;
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SLEntryPtr update[SL_MAX_LEVEL + 1];
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SLEntryPtr entry;
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entry = SLLocate(list, key, update);
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if (entry && entry->key == key) {
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*value = entry;
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return 0;
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}
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*value = NULL;
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return -1;
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}
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int drmSLLookupNeighbors(void *l, unsigned long key,
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unsigned long *prev_key, void **prev_value,
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unsigned long *next_key, void **next_value)
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{
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SkipListPtr list = (SkipListPtr)l;
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SLEntryPtr update[SL_MAX_LEVEL + 1];
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SLEntryPtr entry;
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int retcode = 0;
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entry = SLLocate(list, key, update);
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*prev_key = *next_key = key;
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*prev_value = *next_value = NULL;
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if (update[0]) {
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*prev_key = update[0]->key;
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*prev_value = update[0]->value;
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++retcode;
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if (update[0]->forward[0]) {
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*next_key = update[0]->forward[0]->key;
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*next_value = update[0]->forward[0]->value;
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++retcode;
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}
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}
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return retcode;
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}
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int drmSLNext(void *l, unsigned long *key, void **value)
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{
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SkipListPtr list = (SkipListPtr)l;
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SLEntryPtr entry;
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if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */
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entry = list->p0;
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if (entry) {
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list->p0 = entry->forward[0];
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*key = entry->key;
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*value = entry->value;
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return 1;
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}
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list->p0 = NULL;
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return 0;
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}
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int drmSLFirst(void *l, unsigned long *key, void **value)
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{
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SkipListPtr list = (SkipListPtr)l;
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if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */
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list->p0 = list->head->forward[0];
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return drmSLNext(list, key, value);
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}
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/* Dump internal data structures for debugging. */
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void drmSLDump(void *l)
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{
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SkipListPtr list = (SkipListPtr)l;
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SLEntryPtr entry;
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int i;
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if (list->magic != SL_LIST_MAGIC) {
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printf("Bad magic: 0x%08lx (expected 0x%08lx)\n",
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list->magic, SL_LIST_MAGIC);
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return;
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}
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printf("Level = %d, count = %d\n", list->level, list->count);
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for (entry = list->head; entry; entry = entry->forward[0]) {
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if (entry->magic != SL_ENTRY_MAGIC) {
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printf("Bad magic: 0x%08lx (expected 0x%08lx)\n",
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list->magic, SL_ENTRY_MAGIC);
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}
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printf("\nEntry %p <0x%08lx, %p> has %2d levels\n",
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entry, entry->key, entry->value, entry->levels);
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for (i = 0; i < entry->levels; i++) {
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if (entry->forward[i]) {
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printf(" %2d: %p <0x%08lx, %p>\n",
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i,
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entry->forward[i],
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entry->forward[i]->key,
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entry->forward[i]->value);
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} else {
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printf(" %2d: %p\n", i, entry->forward[i]);
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}
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}
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}
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}
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#if SL_MAIN
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static void print(SkipListPtr list)
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{
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unsigned long key;
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void *value;
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if (drmSLFirst(list, &key, &value)) {
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do {
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printf("key = %5lu, value = %p\n", key, value);
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} while (drmSLNext(list, &key, &value));
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}
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}
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static double do_time(int size, int iter)
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{
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SkipListPtr list;
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int i, j;
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unsigned long keys[1000000];
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unsigned long previous;
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unsigned long key;
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void *value;
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struct timeval start, stop;
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double usec;
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SL_RANDOM_DECL;
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SL_RANDOM_INIT(12345);
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list = drmSLCreate();
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for (i = 0; i < size; i++) {
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keys[i] = SL_RANDOM;
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drmSLInsert(list, keys[i], NULL);
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}
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previous = 0;
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if (drmSLFirst(list, &key, &value)) {
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do {
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if (key <= previous) {
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printf( "%lu !< %lu\n", previous, key);
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}
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previous = key;
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} while (drmSLNext(list, &key, &value));
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}
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gettimeofday(&start, NULL);
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for (j = 0; j < iter; j++) {
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for (i = 0; i < size; i++) {
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if (drmSLLookup(list, keys[i], &value))
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printf("Error %lu %d\n", keys[i], i);
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}
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}
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gettimeofday(&stop, NULL);
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usec = (double)(stop.tv_sec * 1000000 + stop.tv_usec
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- start.tv_sec * 1000000 - start.tv_usec) / (size * iter);
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printf("%0.2f microseconds for list length %d\n", usec, size);
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drmSLDestroy(list);
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return usec;
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}
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static void print_neighbors(void *list, unsigned long key)
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{
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unsigned long prev_key = 0;
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unsigned long next_key = 0;
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void *prev_value;
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void *next_value;
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int retval;
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retval = drmSLLookupNeighbors(list, key,
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&prev_key, &prev_value,
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&next_key, &next_value);
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printf("Neighbors of %5lu: %d %5lu %5lu\n",
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key, retval, prev_key, next_key);
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}
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int main(void)
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{
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SkipListPtr list;
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double usec, usec2, usec3, usec4;
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list = drmSLCreate();
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printf( "list at %p\n", list);
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print(list);
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printf("\n==============================\n\n");
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drmSLInsert(list, 123, NULL);
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drmSLInsert(list, 213, NULL);
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drmSLInsert(list, 50, NULL);
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print(list);
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printf("\n==============================\n\n");
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print_neighbors(list, 0);
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print_neighbors(list, 50);
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print_neighbors(list, 51);
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print_neighbors(list, 123);
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print_neighbors(list, 200);
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print_neighbors(list, 213);
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print_neighbors(list, 256);
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printf("\n==============================\n\n");
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drmSLDelete(list, 50);
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print(list);
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printf("\n==============================\n\n");
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drmSLDump(list);
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drmSLDestroy(list);
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printf("\n==============================\n\n");
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usec = do_time(100, 10000);
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usec2 = do_time(1000, 500);
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printf("Table size increased by %0.2f, search time increased by %0.2f\n",
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1000.0/100.0, usec2 / usec);
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usec3 = do_time(10000, 50);
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printf("Table size increased by %0.2f, search time increased by %0.2f\n",
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10000.0/100.0, usec3 / usec);
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usec4 = do_time(100000, 4);
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printf("Table size increased by %0.2f, search time increased by %0.2f\n",
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100000.0/100.0, usec4 / usec);
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return 0;
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}
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#endif
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