text: /* drmsl.c -- Skip list test
   * Created: Mon May 10 09:28:13 1999 by faith@precisioninsight.com
   *
   * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
   * All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * 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 expected_prev,
                              unsigned long expected_next)
  {
      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);
      if (prev_key != expected_prev) {
          fprintf(stderr, "Unexpected neighbor: %5lu. Expected: %5lu\n",
                  prev_key, expected_prev);
  	exit(1);
      }
      if (next_key != expected_next) {
          fprintf(stderr, "Unexpected neighbor: %5lu. Expected: %5lu\n",
                  next_key, expected_next);
  	exit(1);
      }
  }
  
  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, 0, 50);
      print_neighbors(list, 50, 0, 50);
      print_neighbors(list, 51, 50, 123);
      print_neighbors(list, 123, 50, 123);
      print_neighbors(list, 200, 123, 213);
      print_neighbors(list, 213, 123, 213);
      print_neighbors(list, 256, 213, 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;
  }
  