[C] hash table for C

[출처] http://www.sourcecodesworld.com/source/show.asp?ScriptID=1188

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

typedef struct _node{
 char *name;
 char *desc;
 struct _node *next;
}node;

#define HASHSIZE 101
static node* hashtab[HASHSIZE];

void inithashtab(){
 int i;
 for(i=0;i<HASHSIZE;i++)
  hashtab[i]=NULL;
}

unsigned int hash(char *s){
 unsigned int h=0;
 for(;*s;s++)
  h=*s+h*31;
 return h%HASHSIZE;
}

node* lookup(char *n){
 unsigned int hi=hash(n);
 node* np=hashtab[hi];
 for(;np!=NULL;np=np->next){
  if(!strcmp(np->name,n))
   return np;
 }

 return NULL;
}

char* m_strdup(char *o){
 int l=strlen(o)+1;
 char *ns=(char*)malloc(l*sizeof(char));
 strcpy(ns,o);
 if(ns==NULL)
  return NULL;
 else
  return ns;
}

char* get(char* name){
 node* n=lookup(name);
 if(n==NULL)
  return NULL;
 else
  return n->desc;
}

int install(char* name,char* desc){
 unsigned int hi;
 node* np;
 if((np=lookup(name))==NULL){
  hi=hash(name);
  np=(node*)malloc(sizeof(node));
  if(np==NULL)
   return 0;
  np->name=m_strdup(name);
  if(np->name==NULL) return 0;
  np->next=hashtab[hi];
  hashtab[hi]=np;
 }
 else
  free(np->desc);
 np->desc=m_strdup(desc);
 if(np->desc==NULL) return 0;

 return 1;
}

/* A pretty useless but good debugging function,
  which simply displays the hashtable in (key.value) pairs
*/
void displaytable(){
 int i;
 node *t;
 for(i=0;i<HASHSIZE;i++){
  if(hashtab[i]==NULL)
   printf("() ");
  else{
   t=hashtab[i];
   printf("(");
   for(;t!=NULL;t=t->next)
 printf("(%s.%s) ",t->name,t->desc);
   printf(") ");
  }
 }
}

void cleanup(){
 int i;
 node *np,*t;
 for(i=0;i<HASHSIZE;i++){
  if(hashtab[i]!=NULL){
   np=hashtab[i];
   while(np!=NULL){
 t=np->next;
 free(np->name);
 free(np->desc);
 free(np);
 np=t;
   }
  }
 }
}

#ifdef __TEST_MAIN__
int main(int argc, char *argv[]){
 int i;
 char* names[]={"name","address","phone","k101","k110", "k110"};
 char* descs[]={"Sourav","Sinagor","26300788","Value1","Value2", "Value3"};
 FILE *fp = NULL;

 inithashtab();
 for(i=0;i<6;i++)
  install(names[i],descs[i]);

 printf("Done ");
 printf("If we didnt do anything wrong.." "we should see %s ",get("k110"));

 install("phone","9433120451");

 printf("Again if we go right, we have %s and %s ",get("k101"),get("phone"));

 displaytable();
 cleanup();
 return 0;
}
#endif