symtab.c

tiny 编译器程序的设计 修改了原作者的程序 现在能生成中间代码

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

#define SIZE 211
#define SHIFT 4
/* the hash function */
static int hash(char * key)
{
	int temp = 0;
	int i=0;;
	while ( key[i] != '\0')
	{temp = ((temp << SHIFT) + key[i]) % SIZE;
	 ++i;
	} 
	return temp;
}

typedef struct LineListRec
{ int lineno;
struct LineListRec *next;
}*LineList;

typedef struct BucketListRec
{ char *name;
  LineList lines;
  int memloc;
  struct BucketListRec *next;
} *BucketList;
static BucketList hashTable[SIZE];

void  st_insert(char *name,int lineno,int loc)
{
	int h=hash(name);
    BucketList l=hashTable[h];
    while((l!=NULL)&&(strcmp(name,l->name)!=0))
	{l=l->next;}
   if(l==NULL) 
   { l=(BucketList)malloc(sizeof(struct BucketListRec));
     l->name=name;
	 l->lines=(LineList)malloc(sizeof(struct LineListRec));
     l->lines->lineno=lineno;
     l->memloc=loc;
     l->lines->next=NULL;
     l->next=hashTable[h];
     hashTable[h]=l;}
   else 
   { LineList t=l->lines;
     while(t->next!=NULL) {t=t->next;}
    t->next=(LineList)malloc(sizeof(struct LineListRec));
    t->next->lineno=lineno;
    t->next->next=NULL;
}
}//st_insert





int st_lookup(char *name)
{int h=hash(name);
 BucketList l=hashTable[h];
while((l!=NULL)&&(strcmp(name,l->name)!=0))
l=l->next;
if(l==NULL) return -1;
else return l->memloc;

}
/* procedure printSymTab prints a formatted 
 * listing of the symbol table contents 
 * to the listing file
 */
void printSymTab(FILE *listing)
{ 
	int i;
fprintf(listing,"Variable Name Location Line Numbers\n");
fprintf(listing,"-----------  ---------  --------\n");
for(i=0;i<SIZE;i++)
{if(hashTable[i]!=NULL)
{BucketList l=hashTable[i];
while (l!=NULL)
{LineList t=l->lines;
fprintf(listing,"%-14s",l->name);
fprintf(listing,"%-8d  ",l->memloc);
while(t!=NULL)
{fprintf(listing,"%4d",t->lineno);
t=t->next;
}
fprintf(listing,"\n");
l=l->next;
}
}
}
}//printSymTab