#include "usg_common.h"
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#include "hashtable.h"
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#include "mm.h"
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typedef struct tailq_entry_t
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{
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void *value;
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int key;
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/*
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* This holds the pointers to the next and previous joint in
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* the tail queue.
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*/
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TAILQ_ENTRY(tailq_entry_t) joint;
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} tailq_entry_t;
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typedef TAILQ_HEAD(tailq_header_t, tailq_entry_t) tailq_header_t;
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static size_t hashcode(int key);
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void hashtable_init(hashtable_t *hashtable )
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{
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memset(hashtable, 0, sizeof(hashtable_t));
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}
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void *hashtable_get(hashtable_t *hashtable, int key)
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{
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size_t code = hashcode(key);
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tailq_entry_t *item;
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tailq_header_t *my_tailq_head = hashtable->array[code] ;
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if ( my_tailq_head == NULL)
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{
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return NULL;
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}
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else
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{
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TAILQ_FOREACH(item, my_tailq_head, joint)
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{
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if (key == item->key)
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return item->value;
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}
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}
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return NULL;
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}
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void* hashtable_put(hashtable_t *hashtable, int key, void *value)
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{
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size_t code = hashcode(key);
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void *oldvalue;
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tailq_entry_t *item;
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tailq_header_t *my_tailq_head = hashtable->array[code] ;
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if ( my_tailq_head == NULL)
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{
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my_tailq_head = (tailq_header_t*) mm_malloc(sizeof(tailq_header_t ));
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TAILQ_INIT(my_tailq_head);
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hashtable->array[code] = my_tailq_head;
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goto putnew;
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}
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TAILQ_FOREACH(item, my_tailq_head, joint)
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{
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if (key ==item->key)
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{
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oldvalue = item -> value;
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item->key= key;
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item -> value = value;
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return oldvalue;
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}
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}
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putnew:
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item = (tailq_entry_t *) mm_malloc(sizeof(tailq_entry_t));
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item->key = key;
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item -> value = value;
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TAILQ_INSERT_TAIL(my_tailq_head, item, joint);
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return NULL;
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}
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void *hashtable_remove(hashtable_t *hashtable, int key)
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{
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size_t code = hashcode(key);
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tailq_entry_t *item;
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void *oldvalue;
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tailq_header_t *my_tailq_head = hashtable->array[code] ;
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if ( my_tailq_head == NULL)
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{
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return NULL;
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}
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else
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{
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for (item = TAILQ_FIRST(my_tailq_head); item != NULL; item = TAILQ_NEXT(item, joint))
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{
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if (key == item->key)
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{
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oldvalue = item->value;
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/* Remove the item from the tail queue. */
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TAILQ_REMOVE(my_tailq_head, item, joint);
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/* mm_free the item as we don't need it anymore. */
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mm_free(item);
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return oldvalue;
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}
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}
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}
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return NULL;
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}
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void hashtable_removeall(hashtable_t *hashtable)
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{
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tailq_entry_t *item;
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for (int i = 0; i < MAPSIZE; i++)
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{
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tailq_header_t *my_tailq_head = hashtable->array[i] ;
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if (my_tailq_head == NULL )
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continue;
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while ((item = TAILQ_FIRST(my_tailq_head)) )
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{
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TAILQ_REMOVE(my_tailq_head, item, joint);
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mm_free(item);
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}
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mm_free(my_tailq_head);
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hashtable->array[i] = NULL;
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}
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}
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/**
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* for debug
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*/
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void hashtable_printall(hashtable_t *hashtable)
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{
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tailq_entry_t *item;
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for (int i = 0; i < MAPSIZE; i++)
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{
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tailq_header_t *my_tailq_head = hashtable->array[i] ;
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if (my_tailq_head == NULL )
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continue;
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printf("code=%d\n", i);
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TAILQ_FOREACH(item, my_tailq_head, joint)
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{
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printf("%d:%s\n", item->key, (char *)item->value);
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}
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printf("\n");
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}
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}
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static size_t hashcode(int key)
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{
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return key % MAPSIZE;
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/*printf("hashfun = %ld\n", code);*/
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}
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