aus_sammelwut/paulchen/ublu/ss08/abgabe/gesamt/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                 if(element->param_index!=-1) {
  19                         new_tablex=table_add_param(new_tablex,element->identifier,element->param_index);
  20                 }
  21                 else {
  22                         new_tablex=table_add_symbol(new_tablex,element->identifier,element->type,0,element->stack_offset);
  23                 }
  24                 element=element->next;
  25         }
  26
  27         return new_tablex;
  28 }
  29
  30 struct symbol_t *table_add_symbol(struct symbol_t *table, char *identifier, short type, short check, int stack_offset) {
  31         struct symbol_t *element;
  32         struct symbol_t *new_element;
  33
  34         if(table_lookup(table,identifier)!=(struct symbol_t *)NULL) {
  35                 if(check) {
  36                         fprintf(stderr,"Duplicate field %s.\n",identifier);
  37                         exit(3);
  38                 }
  39
  40                 table=table_remove_symbol(table,identifier);
  41         }
  42
  43         new_element=(struct symbol_t *)malloc(sizeof(struct symbol_t));
  44         new_element->next=(struct symbol_t *)NULL;
  45         new_element->identifier=strdup(identifier);
  46         new_element->type=type;
  47         new_element->stack_offset=stack_offset;
  48         new_element->param_index=-1;
  49
  50         if((struct symbol_t *)NULL==table) {
  51                 return new_element;
  52         }
  53         element=table;
  54
  55         while((struct symbol_t *)NULL!=element->next) {
  56                 element=element->next;
  57         }
  58
  59         element->next=new_element;
  60
  61         return table;
  62 }
  63
  64 struct symbol_t *table_add_param(struct symbol_t *table, char *identifier, int param_index) {
  65         struct symbol_t *element;
  66         struct symbol_t *new_element;
  67
  68         if(table_lookup(table,identifier)!=(struct symbol_t *)NULL) {
  69                 table=table_remove_symbol(table,identifier);
  70         }
  71
  72         new_element=(struct symbol_t *)malloc(sizeof(struct symbol_t));
  73         new_element->next=(struct symbol_t *)NULL;
  74         new_element->identifier=strdup(identifier);
  75         new_element->type=SYMBOL_TYPE_PARAM;
  76         new_element->param_index=param_index;
  77
  78         if((struct symbol_t *)NULL==table) {
  79                 return new_element;
  80         }
  81         element=table;
  82
  83         while((struct symbol_t *)NULL!=element->next) {
  84                 element=element->next;
  85         }
  86
  87         element->next=new_element;
  88
  89         return table;
  90 }
  91
  92 struct symbol_t *table_lookup(struct symbol_t *table, char *identifier) {
  93         struct symbol_t *element;
  94
  95         element=table;
  96
  97         if((struct symbol_t *)NULL==table) {
  98                 return (struct symbol_t *)NULL;
  99         }
 100
 101         if(strcmp(element->identifier,identifier)==0) {
 102                 return element;
 103         }
 104
 105         while((struct symbol_t *)NULL!=element->next) {
 106                 element=element->next;
 107                 if(strcmp(element->identifier,identifier)==0) {
 108                         return element;
 109                 }
 110         }
 111
 112         return (struct symbol_t *)NULL;
 113 }
 114
 115 struct symbol_t *table_merge(struct symbol_t *table, struct symbol_t *to_add, short check) {
 116         struct symbol_t *element;
 117         struct symbol_t *new_table=clone_table(table);
 118
 119         element=to_add;
 120         while(element!=(struct symbol_t *)NULL) {
 121                 if(element->param_index!=-1) {
 122                         new_table=table_add_param(new_table,element->identifier,element->param_index);
 123                 }
 124                 else {
 125                         new_table=table_add_symbol(new_table,element->identifier,element->type,check,element->stack_offset);
 126                 }
 127                 element=element->next;
 128         }
 129
 130         return new_table;
 131 }
 132
 133 struct symbol_t *table_remove_symbol(struct symbol_t *table, char *identifier) {
 134         struct symbol_t *element;
 135         struct symbol_t *previous_element;
 136         struct symbol_t *new_element;
 137
 138         if((struct symbol_t *)NULL==table) {
 139                 return table;
 140         }
 141
 142         previous_element=(struct symbol_t *)NULL;
 143         element=table;
 144
 145         while((struct symbol_t *)NULL!=element) {
 146                 if(strcmp(element->identifier,identifier)==0) {
 147                         if((struct symbol_t *)NULL==previous_element) {
 148                                 new_element=element->next;
 149                         }
 150                         else {
 151                                 previous_element->next=element->next;
 152                                 new_element=table;
 153                         }
 154                         (void)free(element->identifier);
 155                         (void)free(element);
 156                         return new_element;
 157                 }
 158                 previous_element=element;
 159                 element=element->next;
 160         }
 161
 162         return table;
 163 }
 164
 165 void check_variable(struct symbol_t *table, char *identifier) {
 166         struct symbol_t *element=table_lookup(table,identifier);
 167         if(element!=(struct symbol_t *)NULL) {
 168                 if(element->type!=SYMBOL_TYPE_VAR && element->type!=SYMBOL_TYPE_PARAM) {
 169                         fprintf(stderr,"Identifier %s not a variable.\n",identifier);
 170                         exit(3);
 171                 }
 172         }
 173         else {
 174                 fprintf(stderr,"Unknown identifier %s.\n",identifier);
 175                 exit(3);
 176         }
 177 }
 178
 179 void check_field(struct symbol_t *table, char *identifier) {
 180         struct symbol_t *element=table_lookup(table,identifier);
 181         if(element!=(struct symbol_t *)NULL) {
 182                 if(element->type!=SYMBOL_TYPE_FIELD) {
 183                         fprintf(stderr,"Identifier %s not a variable.\n",identifier);
 184                         exit(3);
 185                 }
 186         }
 187         else {
 188                 fprintf(stderr,"Unknown identifier %s.\n",identifier);
 189                 exit(3);
 190         }
 191 }
 192