aus_sammelwut/paulchen/ublu/ss08/abgabe/codea/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,element->stack_offset);
  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, int stack_offset) {
  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         new_element->stack_offset=stack_offset;
  43         new_element->param_index=-1;
  44
  45         if((struct symbol_t *)NULL==table) {
  46                 return new_element;
  47         }
  48         element=table;
  49
  50         while((struct symbol_t *)NULL!=element->next) {
  51                 element=element->next;
  52         }
  53
  54         element->next=new_element;
  55
  56         return table;
  57 }
  58
  59 struct symbol_t *table_add_param(struct symbol_t *table, char *identifier, int param_index) {
  60         struct symbol_t *element;
  61         struct symbol_t *new_element;
  62
  63         if(table_lookup(table,identifier)!=(struct symbol_t *)NULL) {
  64                 table=table_remove_symbol(table,identifier);
  65         }
  66
  67         new_element=(struct symbol_t *)malloc(sizeof(struct symbol_t));
  68         new_element->next=(struct symbol_t *)NULL;
  69         new_element->identifier=strdup(identifier);
  70         new_element->type=SYMBOL_TYPE_PARAM;
  71         new_element->param_index=param_index;
  72
  73         if((struct symbol_t *)NULL==table) {
  74                 return new_element;
  75         }
  76         element=table;
  77
  78         while((struct symbol_t *)NULL!=element->next) {
  79                 element=element->next;
  80         }
  81
  82         element->next=new_element;
  83
  84         return table;
  85 }
  86
  87 struct symbol_t *table_lookup(struct symbol_t *table, char *identifier) {
  88         struct symbol_t *element;
  89
  90         element=table;
  91
  92         if((struct symbol_t *)NULL==table) {
  93                 return (struct symbol_t *)NULL;
  94         }
  95
  96         if(strcmp(element->identifier,identifier)==0) {
  97                 return element;
  98         }
  99
 100         while((struct symbol_t *)NULL!=element->next) {
 101                 element=element->next;
 102                 if(strcmp(element->identifier,identifier)==0) {
 103                         return element;
 104                 }
 105         }
 106
 107         return (struct symbol_t *)NULL;
 108 }
 109
 110 struct symbol_t *table_merge(struct symbol_t *table, struct symbol_t *to_add, short check) {
 111         struct symbol_t *element;
 112         struct symbol_t *new_table=clone_table(table);
 113
 114         element=to_add;
 115         while(element!=(struct symbol_t *)NULL) {
 116                 if(element->param_index!=-1) {
 117                         new_table=table_add_param(new_table,element->identifier,element->param_index);
 118                 }
 119                 else {
 120                         new_table=table_add_symbol(new_table,element->identifier,element->type,check,element->stack_offset);
 121                 }
 122                 element=element->next;
 123         }
 124
 125         return new_table;
 126 }
 127
 128 struct symbol_t *table_remove_symbol(struct symbol_t *table, char *identifier) {
 129         struct symbol_t *element;
 130         struct symbol_t *previous_element;
 131         struct symbol_t *new_element;
 132
 133         if((struct symbol_t *)NULL==table) {
 134                 return table;
 135         }
 136
 137         previous_element=(struct symbol_t *)NULL;
 138         element=table;
 139
 140         while((struct symbol_t *)NULL!=element) {
 141                 if(strcmp(element->identifier,identifier)==0) {
 142                         if((struct symbol_t *)NULL==previous_element) {
 143                                 new_element=element->next;
 144                         }
 145                         else {
 146                                 previous_element->next=element->next;
 147                                 new_element=table;
 148                         }
 149                         (void)free(element->identifier);
 150                         (void)free(element);
 151                         return new_element;
 152                 }
 153                 previous_element=element;
 154                 element=element->next;
 155         }
 156
 157         return table;
 158 }
 159
 160 void check_variable(struct symbol_t *table, char *identifier) {
 161         struct symbol_t *element=table_lookup(table,identifier);
 162         if(element!=(struct symbol_t *)NULL) {
 163                 if(element->type!=SYMBOL_TYPE_VAR && element->type!=SYMBOL_TYPE_PARAM) {
 164                         fprintf(stderr,"Identifier %s not a variable.\n",identifier);
 165                         exit(3);
 166                 }
 167         }
 168         else {
 169                 fprintf(stderr,"Unknown identifier %s.\n",identifier);
 170                 exit(3);
 171         }
 172 }
 173
 174 void check_field(struct symbol_t *table, char *identifier) {
 175         struct symbol_t *element=table_lookup(table,identifier);
 176         if(element!=(struct symbol_t *)NULL) {
 177                 if(element->type!=SYMBOL_TYPE_FIELD) {
 178                         fprintf(stderr,"Identifier %s not a variable.\n",identifier);
 179                         exit(3);
 180                 }
 181         }
 182         else {
 183                 fprintf(stderr,"Unknown identifier %s.\n",identifier);
 184                 exit(3);
 185         }
 186 }
 187