skiplist/examples/ex1.c
2024-05-28 11:05:39 -04:00

387 lines
11 KiB
C

#pragma GCC push_options
#pragma GCC optimize("O0")
// OPTIONS to set before including sl.h
// ---------------------------------------------------------------------------
#define DEBUG
#define SKIPLIST_DIAGNOSTIC
// Include our monolithic ADT, the Skiplist!
// ---------------------------------------------------------------------------
#include "../include/sl.h"
// Local demo application OPTIONS:
// ---------------------------------------------------------------------------
#define TEST_ARRAY_SIZE 10
#define VALIDATE
// define SNAPSHOTS
// define TODO_RESTORE_SNAPSHOTS
#define STABLE_SEED
#define DOT
#ifdef DOT
size_t gen = 0;
FILE *of = 0;
#endif
// ---------------------------------------------------------------------------
#ifdef VALIDATE
#define CHECK __skip_integrity_check_ex(list, 0)
#else
#define CHECK ((void)0)
#endif
/*
* SKIPLIST EXAMPLE:
*
* This example creates an "ex" Skiplist where keys are integers, values are
* strings containing the roman numeral for the key allocated on the heap.
*/
/*
* 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 -> char [] on the heap, 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.
*/
struct ex_node {
int key;
char *value;
SKIPLIST_ENTRY(ex) entries;
};
/*
* Generate all the access functions for our type of Skiplist.
*/
SKIPLIST_DECL(
ex, api_, entries,
/* compare entries: list, a, b, aux */
{
(void)list;
(void)aux;
if (a->key < b->key)
return -1;
if (a->key > b->key)
return 1;
return 0;
},
/* free entry: node */
{
free(node->value);
node->value = NULL;
},
/* update entry: rc, node, value */
{
char *numeral = (char *)value;
if (node->value)
free(node->value);
node->value = numeral;
},
/* archive an entry: rc, src, dest */
{
dest->key = src->key;
char *nv = calloc(strlen(src->value) + 1, sizeof(char));
if (nv == NULL)
rc = ENOMEM;
else {
strncpy(nv, src->value, strlen(src->value));
dest->value = nv;
}
},
/* size in bytes of the content stored in an entry: bytes */
{ bytes = strlen(node->value) + 1; })
/*
* Skiplists are ordered, we need a way to compare entries.
* Let's create a function with four arguments:
* - 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.
*
* Your function should result in a return statement:
* a < b : return -1
* a == b : return 0
* a > b : return 1
*
* This result provides the ordering within the Skiplist. Sometimes
* 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
* list or when `a == b`. In those cases the comparison function
* returns before using the code in your block, don't panic. :)
int
__ex_key_compare(ex_t *list, ex_node_t *a, ex_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;
}
*/
/*
* Optional: Getters and Setters
* - get, put, dup(put), del, etc. functions
*
* 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.
*/
SKIPLIST_DECL_ACCESS(
ex, api_, key, int, value, char *,
/* query blk */ { query.key = key; },
/* return blk */ { return node->value; })
/*
* Optional: Snapshots
*
* Enable functions that enable returning to an earlier point in
* time when a snapshot was created.
*/
SKIPLIST_DECL_SNAPSHOTS(ex, api_, entries)
/*
* Optional: Archive to/from bytes
*
* Enable functions that can write/read the content of your Skiplist
* out/in to/from an array of bytes.
*/
// TODO SKIPLIST_DECL_ARCHIVE(ex, api_, entries)
/*
* Optional: As Hashtable
*
* Turn your Skiplist into a hash table.
*/
// TODO SKIPLIST_DECL_HASHTABLE(ex, api_, entries, snaps)
/*
* Optional: Check Skiplists at runtime
*
* Create a functions that validate the integrity of a Skiplist.
*/
SKIPLIST_DECL_VALIDATE(ex, api_, entries)
/* Optional: Visualize your Skiplist using DOT/Graphviz in PDF
*
* Create the functions used to annotate a visualization of a Skiplist.
*/
SKIPLIST_DECL_DOT(ex, api_, entries)
static void
sprintf_ex_node(ex_node_t *node, char *buf)
{
sprintf(buf, "%d:%s", node->key, node->value);
}
// Function for this demo application.
// ---------------------------------------------------------------------------
/* convert a number into the Roman numeral equivalent, allocates a string caller must free */
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.
char *res = (char *)calloc(4096, sizeof(char));
int i = 0;
if (num < 0) {
res[0] = '-';
i++;
num = -num;
}
if (num == 0) {
res[0] = '0';
return res;
}
if (num > 10000) {
sprintf(res, "The person you were looking for is not here, their mailbox is full, good bye.");
return res;
}
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
}
i++; // proceed to the next key value
}
return res;
}
/* calculate the floor of the log base 2 of a number m (⌊log2(m)⌋) */
static int
floor_log2(unsigned int m)
{
return (int)floor(log(m) / log(2));
}
#ifdef TODO_RESTORE_SNAPSHOTS
typedef struct {
size_t length;
size_t key;
size_t snap_id;
} snap_info_t;
#endif
// ---------------------------------------------------------------------------
/* The head node's height is always 1 more than the tallest node, that location
is where we store the total hits, or "m". */
#define splay_list_m(m) list->slh_head->entries.sle_levels[list->slh_head->entries.sle_height].hits
int
main()
{
int rc;
char *numeral;
#ifdef DOT
char msg[1024];
memset(msg, 0, 1024);
#endif
#ifdef TODO_RESTORE_SNAPSHOTS
size_t n_snaps = 0;
snap_info_t snaps[TEST_ARRAY_SIZE * 2 + 1];
#endif
#ifdef DOT
of = fopen("/tmp/ex1.dot", "w");
if (!of) {
perror("Failed to open file /tmp/ex1.dot");
return 1;
}
#endif
/* Allocate and initialize a Skiplist. */
ex_t *list = (ex_t *)malloc(sizeof(ex_t));
if (list == NULL)
return ENOMEM;
rc = api_skip_init_ex(list);
if (rc)
return rc;
/* Set the PRNG state to a known constant for reproducible generation, easing debugging. */
list->slh_prng_state = 12;
#ifdef SNAPSHOTS
api_skip_snapshots_init_ex(list);
#endif
#ifdef DOT
api_skip_dot_ex(of, list, gen++, "init", sprintf_ex_node);
#endif
/* This example mirrors the example given in the paper about splay-lists
to test implementation against research. */
for (int i = 1; i < 8; i++) {
numeral = int_to_roman_numeral(i);
if ((rc = api_skip_put_ex(list, i, numeral)))
perror("put failed");
#ifdef DOT
sprintf(msg, "put key: %d value: %s", i, numeral);
api_skip_dot_ex(of, list, gen++, msg, sprintf_ex_node);
#endif
}
CHECK;
/* Now we're going to poke around the internals a bit to set things up.
This first time around we're going to build the list by hand, later
we'll ensure that we can build this shape using only API calls. */
ex_node_t *head = list->slh_head;
ex_node_t *tail = list->slh_tail;
ex_node_t *node_1 = head->entries.sle_levels[0].next;
ex_node_t *node_2 = node_1->entries.sle_levels[0].next;
ex_node_t *node_3 = node_2->entries.sle_levels[0].next;
ex_node_t *node_4 = node_3->entries.sle_levels[0].next;
ex_node_t *node_5 = node_4->entries.sle_levels[0].next;
ex_node_t *node_6 = node_5->entries.sle_levels[0].next;
// Head/Tail-nodes are height 3, ...
head->entries.sle_height = tail->entries.sle_height = 3;
// Head-node
head->entries.sle_levels[3].hits = 10;
head->entries.sle_levels[2].hits = 5;
head->entries.sle_levels[1].hits = 1;
head->entries.sle_levels[0].hits = 1;
head->entries.sle_levels[1].next = node_2;
head->entries.sle_levels[2].next = node_6;
head->entries.sle_levels[3].next = tail;
// Tail-node
tail->entries.sle_levels[3].hits = 0;
tail->entries.sle_levels[2].hits = 0;
tail->entries.sle_levels[1].hits = 0;
tail->entries.sle_levels[0].hits = 1;
tail->entries.sle_levels[1].next = tail;
tail->entries.sle_levels[2].next = tail;
tail->entries.sle_levels[3].next = tail;
// First node has key "1", height "0", hits(0) = 1
node_1->entries.sle_height = 0;
node_1->entries.sle_levels[0].hits = 1;
// Second node has key "2", height "1", hits(0) = 1, hits(1) = 0
node_2->entries.sle_height = 1;
node_2->entries.sle_levels[0].hits = 1;
node_2->entries.sle_levels[1].hits = 0;
node_2->entries.sle_levels[1].next = node_3;
// Third node has key "3", height "1", hits(0) = 1, hits(1) = 2
node_3->entries.sle_height = 1;
node_3->entries.sle_levels[0].hits = 1;
node_3->entries.sle_levels[1].hits = 2;
node_3->entries.sle_levels[1].next = node_6;
// Fourth node has key "4", height "0", hits(0) = 1
node_4->entries.sle_height = 0;
node_4->entries.sle_levels[0].hits = 1;
// Fifth node has key "5", height "0", hits(0) = 1
node_5->entries.sle_height = 0;
node_5->entries.sle_levels[0].hits = 1;
// Sixth node has key "6", height "2", hits(0) = 5, hits(1) = 0, hits(2) = 0
node_6->entries.sle_height = 2;
node_6->entries.sle_levels[0].hits = 5;
node_6->entries.sle_levels[1].hits = 0;
node_6->entries.sle_levels[2].hits = 0;
node_6->entries.sle_levels[1].next = tail;
node_6->entries.sle_levels[2].next = tail;
CHECK;
#ifdef DOT
sprintf(msg, "manually adjusted");
api_skip_dot_ex(of, list, gen++, msg, sprintf_ex_node);
#endif
printf("m = %ld; ", splay_list_m(list));
printf("(⌊log2(m)⌋) = %d\n", floor_log2(splay_list_m(list)));
if (!(rc = api_skip_contains_ex(list, 5)))
perror("missing element 5");
#ifdef DOT
sprintf(msg, "contains(5)");
api_skip_dot_ex(of, list, gen++, msg, sprintf_ex_node);
#endif
#ifdef DOT
api_skip_dot_end_ex(of, gen);
fclose(of);
#endif
api_skip_free_ex(list);
free(list);
return rc;
}
#pragma GCC pop_options