ag/symtable.c

   1 #include <string.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include "symtable.h"
   5
   6 struct symbol *new_tab(void)
   7 {
   8         return SYMNULL;
   9 }
  10
  11 struct symbol *clone_tab(struct symbol *tab)
  12 {
  13         struct symbol *elm;
  14         struct symbol *new_tabx;
  15
  16         elm = tab;
  17         new_tabx = new_tab();
  18         while(elm != SYMNULL) {
  19                 new_tabx = tab_add_symbol(new_tabx, elm->ident, elm->type, 0);
  20                 elm = elm->next;
  21         }
  22
  23         return new_tabx;
  24 }
  25
  26 struct symbol *tab_add_symbol(struct symbol *tab, char *ident, short type, short check)
  27 {
  28         struct symbol *elm;
  29         struct symbol *new_elm;
  30
  31         if(tab_lookup(tab, ident) != SYMNULL) {
  32                 if(check) {
  33                         fprintf(stderr, "Feld doppelt vorhanden: \"%s\"\n", ident);
  34                         exit(3);
  35                 } else {
  36                         tab = tab_remove_symbol(tab, ident);
  37                 }
  38         }
  39
  40         new_elm = (struct symbol *) malloc(sizeof(struct symbol));
  41         new_elm->next = SYMNULL;
  42         new_elm->ident = strdup(ident);
  43         new_elm->type = type;
  44
  45         if(tab == SYMNULL) {
  46                 return new_elm;
  47         }
  48
  49         elm = tab;
  50         while(elm->next != SYMNULL) {
  51                 elm = elm->next;
  52         }
  53         elm->next = new_elm;
  54
  55         return tab;
  56 }
  57
  58 struct symbol *tab_lookup(struct symbol *tab, char *ident)
  59 {
  60         struct symbol *elm = tab;
  61
  62         if(tab == SYMNULL) {
  63                 return SYMNULL;
  64         }
  65
  66         do {
  67                 if(strcmp(elm->ident, ident) == 0) {
  68                         return elm;
  69                 }
  70                 elm = elm->next;
  71         } while(elm != SYMNULL);
  72
  73         return SYMNULL;
  74 }
  75
  76 struct symbol *tab_merge(struct symbol *tab, struct symbol *to_add, short check)
  77 {
  78         struct symbol *elm = to_add;
  79         struct symbol *new_tab = clone_tab(tab);
  80
  81         while(elm != SYMNULL) {
  82                 new_tab = tab_add_symbol(new_tab, elm->ident, elm->type, check);
  83                 elm = elm->next;
  84         }
  85
  86         return new_tab;
  87 }
  88
  89 struct symbol *tab_remove_symbol(struct symbol *tab, char *ident)
  90 {
  91         struct symbol *elm = tab;
  92         struct symbol *previous_elm = SYMNULL;
  93
  94         while(elm != SYMNULL) {
  95                 if(strcmp(elm->ident, ident) == 0) {
  96                         if(previous_elm == SYMNULL) {
  97                                 tab = elm->next;
  98                         } else {
  99                                 previous_elm->next = elm->next;
 100                         }
 101                         (void)free(elm->ident);
 102                         (void)free(elm);
 103                         break;
 104                 }
 105                 previous_elm = elm;
 106                 elm = elm->next;
 107         }
 108
 109         return tab;
 110 }
 111
 112 void check_variable(struct symbol *tab, char *ident)
 113 {
 114         struct symbol *elm = tab_lookup(tab, ident);
 115         if(elm != SYMNULL) {
 116                 if(elm->type != S_VAR) {
 117                         fprintf(stderr, "Identifier ist keine Variable: \"%s\"\n", ident);
 118                         exit(3);
 119                 }
 120         } else {
 121                 fprintf(stderr, "Unbekannter Identifier: \"%s\"\n", ident);
 122                 exit(3);
 123         }
 124 }
 125
 126 void check_field(struct symbol *tab, char *ident)
 127 {
 128         struct symbol *elm = tab_lookup(tab, ident);
 129         if(elm != SYMNULL) {
 130                 if(elm->type != S_FIELD) {
 131                         fprintf(stderr, "Identifier ist kein Feld: \"%s\"\n", ident);
 132                         exit(3);
 133                 }
 134         } else {
 135                 fprintf(stderr, "Unbekannter Identifier: \"%s\"\n", ident);
 136                 exit(3);
 137         }
 138 }
 139