4.3BSD - /usr/src/new/spms/src/lib/libhash/src/htinstall.c

   1: /* $Header$ */
   2: 
   3: /*
   4:  * Author: Peter J. Nicklin
   5:  */
   6: 
   7: /*
   8:  * htinstall() installs a new entry in a hash table if it doesn't already
   9:  * exist. If it does, the old definition and value is superseded. Returns
  10:  * a pointer to the entry, or null if out of memory.
  11:  */
  12: #include "null.h"
  13: #include "hash.h"
  14: 
  15: HASHBLK *
  16: htinstall(key, def, val, hash)
  17:     char *key;          /* key for hash table entry */
  18:     char *def;          /* definition string */
  19:     int val;            /* integer value */
  20:     HASH *hash;         /* hash table */
  21: {
  22:     char *malloc();         /* memory allocator */
  23:     char *strsav();         /* save string somewhere */
  24:     HASHBLK *htb;           /* hash table entry block */
  25:     HASHBLK *htlookup();        /* find hash table entry */
  26:     int hashval;            /* hash value for key */
  27:     int hthash();           /* calculate hash value */
  28: 
  29:     if ((htb = htlookup(key, hash)) == NULL)
  30:         {           /* not found */
  31:         if ((htb = (HASHBLK *) malloc(sizeof(HASHBLK))) == NULL)
  32:             return(NULL);
  33:         if ((htb->h_key = strsav(key)) == NULL)
  34:             return(NULL);
  35:         hashval = hthash(key, hash);
  36:         htb->h_next = (hash->hashtab)[hashval];
  37:         (hash->hashtab)[hashval] = htb;
  38:         }
  39:     else    {           /* found */
  40:         free(htb->h_def);   /* free previous definition */
  41:         }
  42:     if ((htb->h_def = strsav(def)) == NULL)
  43:         return(NULL);
  44:     htb->h_val = val;
  45:     return(htb);
  46: }

Defined functions