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Listing 3 hashhmap.cxx implementation of the VPmap class

/*----------------------------------------*
 * .
 */
#include <stdlib.h>
#include "hashmap.h"

/*----------------------------------------*
 * convenient macros
 */
#define ELEMENTS(array) \
       (sizeof(array) / sizeof(array[0]))

#define EACHELEM(x, array, size) \
       x = &(array)[size]; \
       x-- > (array);

VPmap::VPmap
   (size_t            buckets,
    KeyHashProc       key_hash,
    KeyCompareEqProc  key_cmp,
    KeyValCreateProc  K_V_C,
    KeyValDestroyProc K_V_D)
{

   hash               = key_hash;
   isEqual            = key_cmp;
   CreateKeyAndValue  = K_V_C;
   DestroyKeyAndValue = K_V_D;
   hashsize           = buckets;

   VPAssoc **ptr;
   keys = new VPAssoc *[hashsize];
   for (EACHELEM(ptr, keys, hashsize))
       *ptr = NULL;
}


VPmap::~VPmap()
{
   VPAssoc **list;

   for (EACHELEM(list, keys, hashsize))
       while (*list) {
          VPAssoc *item = *list;
          *list = item->next;

          DestroyKeyAndValue(item->key, item->value);
          delete item;
       }

   delete[] keys;
}


void VPmap::apply(VPiterProc proc, void *data)
{
   VPAssoc **list, *item;

   for (EACHELEM(list, keys, hashsize))
       for (item = *list; item != NULL; item = item->next)
          (*proc)(item->key, item->value, data);
}


void *VPmap::index(const void *theKey)
{
    VPAssoc *item, **list = &keys[hash(theKey) % hashsize];
        if (isEqual(theKey, item->key))
           return item->value;
           // Key was not found,
           // creat a new association for this key
    VPAssoc *n = new VPAssoc;
    CreateKeyAndValue(this, theKey, n->key, n->value);
    n->next = *list;
    *list = n;

    return n->value;
}
/* End of File */