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#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "uthash.h"
struct item {
int payload;
UT_hash_handle hh;
};
void delete_without_modifying(struct item *head, const struct item *p)
{
struct item old;
memcpy(&old, p, sizeof(struct item)); // also copy the padding bits
assert(memcmp(&old, p, sizeof(struct item)) == 0);
assert(p->hh.tbl == head->hh.tbl); // class invariant
HASH_DEL(head, p);
assert(memcmp(&old, p, sizeof(struct item)) == 0); // unmodified by HASH_DEL
}
int main()
{
struct item *items = NULL;
struct item *found = NULL;
int fortytwo = 42;
int i;
for (i=0; i < 100; i++) {
struct item *p = (struct item *)malloc(sizeof *p);
p->payload = i;
HASH_ADD_INT(items, payload, p);
}
assert(HASH_COUNT(items) == 100);
// Delete item "42" from the hash, wherever it is.
HASH_FIND_INT(items, &fortytwo, found);
assert(found != NULL);
assert(found->payload == 42);
delete_without_modifying(items, found);
assert(HASH_COUNT(items) == 99);
HASH_FIND_INT(items, &fortytwo, found);
assert(found == NULL);
// Delete the very first item in the hash.
assert(items != NULL);
i = items->payload;
delete_without_modifying(items, items);
assert(HASH_COUNT(items) == 98);
HASH_FIND_INT(items, &i, found);
assert(found == NULL);
// leak the items, we don't care
return 0;
}
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