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