pet-projects/DLW-1e/das/symbol_tbl.c

   1 #include <stdio.h>
   2 #include <string.h>
   3
   4 #include "symbol_tbl.h"
   5 #include "error.h"
   6
   7 struct symbol {
   8         char name[LABEL_LEN];
   9         int value;
  10 };
  11
  12 #define SYM_TBL_MAX_SIZE 16
  13
  14 static size_t symbol_tbl_size;
  15 static struct symbol symbol_tbl[SYM_TBL_MAX_SIZE];
  16
  17 static struct symbol *table_lookup(const char *name)
  18 {
  19         size_t i;
  20
  21         for (i = 0; i < symbol_tbl_size; i++)
  22                 if (!strcmp(name, symbol_tbl[i].name))
  23                         return &symbol_tbl[i];
  24
  25         return NULL;
  26 }
  27
  28 int symbol_tbl_lookup(const char *name)
  29 {
  30         struct symbol *symbol;
  31
  32         symbol = table_lookup(name);
  33         if (!symbol)
  34                 return -1;
  35
  36         return symbol->value;
  37 }
  38
  39 static void fill_symbol(struct symbol *new, const char *name, int value)
  40 {
  41         memset(new, 0, sizeof(struct symbol));
  42         strncpy(new->name, name, LABEL_LEN - 1);
  43         new->value = value;
  44 }
  45
  46 int symbol_tbl_insert(const char *name, int value, int line_nr)
  47 {
  48         struct symbol *sym;
  49
  50         sym = table_lookup(name);
  51         if (sym) {
  52                 error(line_nr, "symbol %s redefined", name);
  53                 return -1;
  54         }
  55
  56         if (symbol_tbl_size == SYM_TBL_MAX_SIZE)
  57                 fatal("symbol table is full");
  58
  59         fill_symbol(&symbol_tbl[symbol_tbl_size], name, value);
  60         symbol_tbl_size++;
  61
  62         return 0;
  63 }
  64
  65 static void dump_symbol(const struct symbol *sym)
  66 {
  67         printf("%s   %d\n", sym->name, sym->value);
  68 }
  69
  70 void symbol_tbl_dump(void)
  71 {
  72         size_t i;
  73
  74         for (i = 0; i < symbol_tbl_size; i++)
  75                 dump_symbol(&symbol_tbl[i]);
  76 }