skiplist/examples/slm.c

249 lines
7.4 KiB
C
Raw Normal View History

2024-03-21 16:30:37 +00:00
#include <sys/time.h>
2024-03-19 18:24:33 +00:00
#include <assert.h>
2024-03-19 01:19:26 +00:00
#include <errno.h>
2024-03-18 18:58:35 +00:00
#include <stddef.h>
2024-03-17 14:40:59 +00:00
#include <stdint.h>
2024-03-19 01:19:26 +00:00
#include <stdio.h>
#include <stdlib.h>
2024-03-21 16:30:37 +00:00
#include <string.h>
#include <time.h>
#include <unistd.h>
2024-03-19 01:19:26 +00:00
2024-03-20 18:33:08 +00:00
/* Setting this will do two things:
* 1) limit our max height across all instances of this datastructure.
* 2) remove a heap allocation on frequently used paths, insert/remove/etc.
* so, use it when you need it.
*/
#define SKIPLIST_MAX_HEIGHT 12
2024-03-17 14:40:59 +00:00
#include "../include/sl.h"
/*
* SKIPLIST EXAMPLE:
*
* This example creates a Skiplist keys and values are integers.
2024-03-18 15:06:49 +00:00
* 'slex' - meaning: SkipList EXample
2024-03-17 14:40:59 +00:00
*/
2024-03-18 18:58:35 +00:00
/*
* To start, you must create a type node that will contain the
* fields you'd like to maintain in your Skiplist. In this case
* we map int -> int, but what you put here is up to you. You
* don't even need a "key", just a way to compare one node against
* another, logic you'll provide in SKIP_DECL as a block below.
*/
2024-03-18 15:06:49 +00:00
struct slex_node {
int key;
2024-03-21 16:30:37 +00:00
char *value;
2024-03-21 13:31:32 +00:00
SKIPLIST_ENTRY(slex_node) entries;
2024-03-17 14:40:59 +00:00
};
2024-03-18 18:58:35 +00:00
/*
* Generate all the access functions for our type of Skiplist.
2024-03-19 13:41:36 +00:00
*/
2024-03-19 16:33:11 +00:00
SKIPLIST_DECL(
slex, api_, entries,
2024-03-21 18:43:10 +00:00
/* free node */ { free(node->value); },
2024-03-20 20:02:56 +00:00
/* update node */ { node->value = new->value; },
2024-03-21 16:30:37 +00:00
/* snapshot node */
{
new->key = node->key;
2024-03-21 18:43:10 +00:00
char *nv = calloc(strlen(node->value) + 1, sizeof(char));
if (nv == NULL)
return NULL; /* leaks some memory... TODO */
new->value = strncpy(nv, node->value, strlen(node->value));
2024-03-21 16:30:37 +00:00
},
/* size in bytes of the content stored in an entry by you */
2024-03-21 18:43:10 +00:00
{ size = strlen(node->value) + 1; })
/* Optional: Create the functions used to visualize a Skiplist (DOT/Graphviz) */
SKIPLIST_DECL_DOT(slex, api_, entries)
void
sprintf_slex_node(slex_node_t *node, char *buf)
{
sprintf(buf, "%d:%s", node->key, node->value);
}
2024-03-19 13:41:36 +00:00
/*
* Getter
* It can be useful to have simple get/put-style API, but to
* do that you'll have to supply some blocks of code used to
* extract data from within your nodes.
*/
2024-03-19 17:22:55 +00:00
SKIPLIST_GETTERS(
2024-03-21 16:30:37 +00:00
slex, api_, int, char *, { query.key = key; }, { return node->value; })
2024-03-19 13:41:36 +00:00
/*
* Now we need a way to compare the nodes you defined above.
* Let's create a function with four arguments:
2024-03-18 18:58:35 +00:00
* - a reference to the Skiplist, `slist`
* - the two nodes to compare, `a` and `b`
* - and `aux`, which you can use to pass into this function
* any additional information required to compare objects.
* `aux` is passed from the value in the Skiplist, you can
* modify that value at any time to suit your needs.
*
2024-03-19 13:41:36 +00:00
* Your function should result in a return statement:
2024-03-18 18:58:35 +00:00
* a < b : return -1
* a == b : return 0
* a > b : return 1
*
* This result provides the ordering within the Skiplist. Sometimes
2024-03-19 13:41:36 +00:00
* your function will not be used when comparing nodes. This will
* happen when `a` or `b` are references to the head or tail of the
2024-03-18 18:58:35 +00:00
* list or when `a == b`. In those cases the comparison function
* returns before using the code in your block, don't panic. :)
*/
2024-03-19 01:19:26 +00:00
int
__slm_key_compare(slex_t *list, slex_node_t *a, slex_node_t *b, void *aux)
{
(void)list;
(void)aux;
if (a->key < b->key)
return -1;
if (a->key > b->key)
return 1;
return 0;
2024-03-19 01:19:26 +00:00
}
2024-03-17 14:40:59 +00:00
2024-03-21 18:43:10 +00:00
static char *
to_lower(char *str)
{
2024-03-21 16:30:37 +00:00
char *p = str;
2024-03-21 18:43:10 +00:00
for (; *p; ++p)
*p = *p >= 'A' && *p <= 'Z' ? *p | 0x60 : *p;
2024-03-21 16:30:37 +00:00
return str;
}
2024-03-21 18:43:10 +00:00
static char *
to_upper(char *str)
{
2024-03-21 16:30:37 +00:00
char *p = str;
2024-03-21 18:43:10 +00:00
for (; *p; ++p)
*p = *p >= 'a' && *p <= 'z' ? *p & ~0x20 : *p;
2024-03-21 16:30:37 +00:00
return str;
}
2024-03-21 18:43:10 +00:00
static char *
int_to_roman_numeral(int num)
{
int del[] = { 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 }; // Key value in Roman counting
char *sym[] = { "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" }; // Symbols for key values
// The maximum length of the Roman numeral representation for the maximum signed 64-bit integer would be approximately 19 * 3 = 57 characters, assuming
// every digit is represented by its Roman numeral equivalent up to 3 repetitions. Therefore, 64 should be more than enough.
2024-03-21 16:30:37 +00:00
char *res = (char *)calloc(64, sizeof(char));
int i = 0;
if (num < 0) {
res[0] = '-';
i++;
num = -num;
}
if (num == 0) {
res[0] = '0';
return res;
}
2024-03-21 18:43:10 +00:00
while (num) { // while input number is not zero
while (num / del[i]) { // while a number contains the largest key value possible
strcat(res, sym[i]); // append the symbol for this key value to res string
num -= del[i]; // subtract the key value from number
2024-03-21 16:30:37 +00:00
}
2024-03-21 18:43:10 +00:00
i++; // proceed to the next key value
2024-03-21 16:30:37 +00:00
}
return res;
}
2024-03-21 18:43:10 +00:00
void
shuffle(int *array, size_t n)
{
2024-03-21 16:30:37 +00:00
if (n > 1) {
size_t i;
for (i = n - 1; i > 0; i--) {
2024-03-21 18:43:10 +00:00
size_t j = (unsigned int)(rand() % (i + 1)); /* NOLINT(*-msc50-cpp) */
2024-03-21 16:30:37 +00:00
int t = array[j];
array[j] = array[i];
array[i] = t;
}
}
}
#define TEST_ARRAY_SIZE 50
2024-03-19 01:19:26 +00:00
int
main()
{
int rc = 0;
2024-03-21 16:30:37 +00:00
/* Allocate and initialize a Skiplist. */
slex_t *list = (slex_t *)malloc(sizeof(slex_t));
2024-03-21 16:30:37 +00:00
if (list == NULL)
return ENOMEM;
rc = api_skip_init_slex(list, 12, __slm_key_compare);
2024-03-19 13:41:36 +00:00
if (rc)
return rc;
2024-03-21 16:30:37 +00:00
/* Test creating a snapshot of an empty Skiplist */
slex_snap_t *snap = api_skip_snapshot_slex(list);
slex_t *restored = api_skip_restore_snapshot_slex(snap, __skip_key_compare_slex);
api_skip_dispose_snapshot_slex(snap);
api_skip_destroy_slex(restored);
/* Insert 7 key/value pairs into the list. */
2024-03-21 16:30:37 +00:00
int amt = TEST_ARRAY_SIZE, asz = (amt * 2) + 1;
int array[(TEST_ARRAY_SIZE * 2) + 1];
for (int j = 0, i = -amt; i <= amt; i++, j++)
array[j] = i;
shuffle(array, asz);
for (int i = 0; i <= asz; i++) {
struct slex_node *n;
char *v;
slex_node_t new;
rc = api_skip_alloc_node_slex(list, &n);
if (rc)
return rc;
2024-03-21 16:30:37 +00:00
n->key = array[i];
n->value = to_lower(int_to_roman_numeral(array[i]));
api_skip_insert_slex(list, n);
2024-03-21 16:30:37 +00:00
v = api_skip_get_slex(list, array[i]);
((void)v);
new.key = n->key;
2024-03-21 16:30:37 +00:00
new.value = to_upper(n->value);
api_skip_update_slex(list, &new);
}
slex_node_t q;
q.key = 0;
api_skip_remove_slex(list, &q);
2024-03-21 16:30:37 +00:00
snap = api_skip_snapshot_slex(list);
restored = api_skip_restore_snapshot_slex(snap, __skip_key_compare_slex);
2024-03-21 02:48:11 +00:00
api_skip_dispose_snapshot_slex(snap);
api_skip_destroy_slex(restored);
2024-03-21 16:30:37 +00:00
assert(api_skip_gte_slex(list, -6) == int_to_roman_numeral(-5));
assert(api_skip_gte_slex(list, -2) == int_to_roman_numeral(-2));
assert(api_skip_gte_slex(list, 0) == int_to_roman_numeral(0));
assert(api_skip_gte_slex(list, 2) == int_to_roman_numeral(2));
assert(api_skip_gte_slex(list, 6) == int_to_roman_numeral(0));
2024-03-21 16:30:37 +00:00
assert(api_skip_lte_slex(list, -6) == int_to_roman_numeral(0));
assert(api_skip_lte_slex(list, -2) == int_to_roman_numeral(-2));
assert(api_skip_lte_slex(list, 0) == int_to_roman_numeral(-10));
assert(api_skip_lte_slex(list, 2) == int_to_roman_numeral(2));
assert(api_skip_lte_slex(list, 6) == int_to_roman_numeral(20));
FILE *of = fopen("/tmp/slm.dot", "w");
if (!of) {
perror("Failed to open file /tmp/slm.dot");
return EXIT_FAILURE;
}
api_skip_dot_slex(of, list, 0, sprintf_slex_node);
fclose(of);
api_skip_destroy_slex(list);
2024-03-19 16:57:29 +00:00
return rc;
2024-03-17 14:40:59 +00:00
}