ag/symbol_table.c

   1 #include <string.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include "symbol_table.h"
   5
   6 struct symbol_t *new_table(void) {
   7         return (struct symbol_t *)NULL;
   8 }
   9
  10 struct symbol_t *clone_table(struct symbol_t *table) {
  11         struct symbol_t *element;
  12         struct symbol_t *new_tablex;
  13
  14         element=table;
  15         new_tablex=new_table();
  16         while((struct symbol_t *)NULL!=element) {
  17                 /* check return value */
  18                 new_tablex=table_add_symbol(new_tablex,element->identifier,element->type,0);
  19                 element=element->next;
  20         }
  21
  22         return new_tablex;
  23 }
  24
  25 struct symbol_t *table_add_symbol(struct symbol_t *table, char *identifier, short type, short check) {
  26         struct symbol_t *element;
  27         struct symbol_t *new_element;
  28
  29         if(table_lookup(table,identifier)!=(struct symbol_t *)NULL) {
  30                 if(check) {
  31                         fprintf(stderr,"Duplicate field %s.\n",identifier);
  32                         exit(3);
  33                 }
  34
  35                 table=table_remove_symbol(table,identifier);
  36         }
  37
  38         new_element=(struct symbol_t *)malloc(sizeof(struct symbol_t));
  39         new_element->next=(struct symbol_t *)NULL;
  40         new_element->identifier=strdup(identifier);
  41         new_element->type=type;
  42
  43         if((struct symbol_t *)NULL==table) {
  44                 return new_element;
  45         }
  46         element=table;
  47
  48         while((struct symbol_t *)NULL!=element->next) {
  49                 element=element->next;
  50         }
  51
  52         element->next=new_element;
  53
  54         return table;
  55 }
  56
  57 struct symbol_t *table_lookup(struct symbol_t *table, char *identifier) {
  58         struct symbol_t *element;
  59
  60         element=table;
  61
  62         if((struct symbol_t *)NULL==table) {
  63                 return (struct symbol_t *)NULL;
  64         }
  65
  66         if(strcmp(element->identifier,identifier)==0) {
  67                 return element;
  68         }
  69
  70         while((struct symbol_t *)NULL!=element->next) {
  71                 element=element->next;
  72                 if(strcmp(element->identifier,identifier)==0) {
  73                         return element;
  74                 }
  75         }
  76
  77         return (struct symbol_t *)NULL;
  78 }
  79
  80 struct symbol_t *table_merge(struct symbol_t *table, struct symbol_t *to_add, short check) {
  81         struct symbol_t *element;
  82         struct symbol_t *new_table=clone_table(table);
  83
  84         element=to_add;
  85         while(element!=(struct symbol_t *)NULL) {
  86                 new_table=table_add_symbol(new_table,element->identifier,element->type,check);
  87                 element=element->next;
  88         }
  89
  90         return new_table;
  91 }
  92
  93 struct symbol_t *table_remove_symbol(struct symbol_t *table, char *identifier) {
  94         struct symbol_t *element;
  95         struct symbol_t *previous_element;
  96         struct symbol_t *new_element;
  97
  98         if((struct symbol_t *)NULL==table) {
  99                 return table;
 100         }
 101
 102         previous_element=(struct symbol_t *)NULL;
 103         element=table;
 104
 105         while((struct symbol_t *)NULL!=element) {
 106                 if(strcmp(element->identifier,identifier)==0) {
 107                         if((struct symbol_t *)NULL==previous_element) {
 108                                 new_element=element->next;
 109                         }
 110                         else {
 111                                 previous_element->next=element->next;
 112                                 new_element=table;
 113                         }
 114                         (void)free(element->identifier);
 115                         (void)free(element);
 116                         return new_element;
 117                 }
 118                 previous_element=element;
 119                 element=element->next;
 120         }
 121
 122         return table;
 123 }
 124
 125 void check_variable(struct symbol_t *table, char *identifier) {
 126         struct symbol_t *element=table_lookup(table,identifier);
 127         if(element!=(struct symbol_t *)NULL) {
 128                 if(element->type!=SYMBOL_TYPE_VAR) {
 129                         fprintf(stderr,"Identifier %s not a variable.\n",identifier);
 130                         exit(3);
 131                 }
 132         }
 133         else {
 134                 fprintf(stderr,"Unknown identifier %s.\n",identifier);
 135                 exit(3);
 136         }
 137 }
 138
 139 void check_field(struct symbol_t *table, char *identifier) {
 140         struct symbol_t *element=table_lookup(table,identifier);
 141         if(element!=(struct symbol_t *)NULL) {
 142                 if(element->type!=SYMBOL_TYPE_FIELD) {
 143                         fprintf(stderr,"Identifier %s not a variable.\n",identifier);
 144                         exit(3);
 145                 }
 146         }
 147         else {
 148                 fprintf(stderr,"Unknown identifier %s.\n",identifier);
 149                 exit(3);
 150         }
 151 }
 152