/[cvs]/stack/stack.c
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revision 1.46 by masse, Thu Feb 7 03:56:39 2002 UTC revision 1.53 by teddy, Thu Feb 7 23:56:54 2002 UTC
# Line 1  Line 1 
1  /* printf */  /* printf, sscanf, fgets, fprintf */
2  #include <stdio.h>  #include <stdio.h>
3  /* EXIT_SUCCESS */  /* exit, EXIT_SUCCESS, malloc, free */
4  #include <stdlib.h>  #include <stdlib.h>
5  /* NULL */  /* NULL */
6  #include <stddef.h>  #include <stddef.h>
7  /* dlopen, dlsym, dlerror */  /* dlopen, dlsym, dlerror */
8  #include <dlfcn.h>  #include <dlfcn.h>
9  /* assert */  /* strcmp, strcpy, strlen, strcat, strdup */
10  #include <assert.h>  #include <string.h>
11    
12  #define HASHTBLSIZE 65536  #define HASHTBLSIZE 65536
13    
# Line 75  void init_env(environment *env) Line 75  void init_env(environment *env)
75      env->symbols[i]= NULL;      env->symbols[i]= NULL;
76  }  }
77    
78    void printerr(const char* in_string) {
79      fprintf(stderr, "Err: %s\n", in_string);
80    }
81    
82    /* Throw away a value */
83    void free_val(value *val){
84      stackitem *item, *temp;
85    
86      val->refcount--;              /* Decrease the reference count */
87      if(val->refcount == 0){
88        switch (val->type){         /* and free the contents if necessary */
89        case string:
90          free(val->content.ptr);
91          break;
92        case list:                  /* lists needs to be freed recursively */
93          item=val->content.ptr;
94          while(item != NULL) {     /* for all stack items */
95            free_val(item->item);   /* free the value */
96            temp=item->next;        /* save next ptr */
97            free(item);             /* free the stackitem */
98            item=temp;              /* go to next stackitem */
99          }
100          free(val);                /* Free the actual list value */
101          break;
102        default:
103          break;
104        }
105      }
106    }
107    
108    /* Discard the top element of the stack. */
109    extern void toss(environment *env)
110    {
111      stackitem *temp= env->head;
112    
113      if((env->head)==NULL) {
114        printerr("Too Few Arguments");
115        env->err=1;
116        return;
117      }
118      
119      free_val(env->head->item);    /* Free the value */
120      env->head= env->head->next;   /* Remove the top stack item */
121      free(temp);                   /* Free the old top stack item */
122    }
123    
124  /* Returns a pointer to a pointer to an element in the hash table. */  /* Returns a pointer to a pointer to an element in the hash table. */
125  symbol **hash(hashtbl in_hashtbl, const char *in_string)  symbol **hash(hashtbl in_hashtbl, const char *in_string)
126  {  {
# Line 149  void push_cstring(stackitem **stack_head Line 195  void push_cstring(stackitem **stack_head
195    push(stack_head, new_item);    push(stack_head, new_item);
196  }  }
197    
198    /* Mangle a symbol name to a valid C identifier name */
199    char *mangle_str(const char *old_string){
200      char validchars[]
201        ="0123456789abcdef";
202      char *new_string, *current;
203    
204      new_string=malloc((strlen(old_string)*2)+4);
205      strcpy(new_string, "sx_");    /* Stack eXternal */
206      current=new_string+3;
207      while(old_string[0] != '\0'){
208        current[0]=validchars[(unsigned char)(old_string[0])/16];
209        current[1]=validchars[(unsigned char)(old_string[0])%16];
210        current+=2;
211        old_string++;
212      }
213      current[0]='\0';
214    
215      return new_string;            /* The caller must free() it */
216    }
217    
218    extern void mangle(environment *env){
219      value *new_value;
220      char *new_string;
221    
222      if((env->head)==NULL) {
223        printerr("Too Few Arguments");
224        env->err=1;
225        return;
226      }
227    
228      if(env->head->item->type!=string) {
229        printerr("Bad Argument Type");
230        env->err=2;
231        return;
232      }
233    
234      new_string= mangle_str((const char *)(env->head->item->content.ptr));
235    
236      toss(env);
237      if(env->err) return;
238    
239      new_value= malloc(sizeof(value));
240      new_value->content.ptr= new_string;
241      new_value->type= string;
242      new_value->refcount=1;
243    
244      push_val(&(env->head), new_value);
245    }
246    
247  /* Push a symbol onto the stack. */  /* Push a symbol onto the stack. */
248  void push_sym(environment *env, const char *in_string)  void push_sym(environment *env, const char *in_string)
249  {  {
# Line 163  void push_sym(environment *env, const ch Line 258  void push_sym(environment *env, const ch
258    void *funcptr;                /* A function pointer */    void *funcptr;                /* A function pointer */
259    
260    static void *handle= NULL;    /* Dynamic linker handle */    static void *handle= NULL;    /* Dynamic linker handle */
261      const char *dlerr;            /* Dynamic linker error */
262      char *mangled;                /* Mangled function name */
263    
264    /* Create a new stack item containing a new value */    /* Create a new stack item containing a new value */
265    new_item= malloc(sizeof(stackitem));    new_item= malloc(sizeof(stackitem));
# Line 195  void push_sym(environment *env, const ch Line 292  void push_sym(environment *env, const ch
292        handle= dlopen(NULL, RTLD_LAZY);        handle= dlopen(NULL, RTLD_LAZY);
293    
294      funcptr= dlsym(handle, in_string); /* Get function pointer */      funcptr= dlsym(handle, in_string); /* Get function pointer */
295      if(dlerror()==NULL) {       /* If a function was found */      dlerr=dlerror();
296        if(dlerr != NULL) {         /* If no function was found */
297          mangled=mangle_str(in_string);
298          funcptr= dlsym(handle, mangled); /* try mangling it */
299          free(mangled);
300          dlerr=dlerror();
301        }
302        if(dlerr==NULL) {           /* If a function was found */
303        new_fvalue= malloc(sizeof(value)); /* Create a new value */        new_fvalue= malloc(sizeof(value)); /* Create a new value */
304        new_fvalue->type=func;    /* The new value is a function pointer */        new_fvalue->type=func;    /* The new value is a function pointer */
305        new_fvalue->content.ptr=funcptr; /* Store function pointer */        new_fvalue->content.ptr=funcptr; /* Store function pointer */
# Line 207  void push_sym(environment *env, const ch Line 311  void push_sym(environment *env, const ch
311    push(&(env->head), new_item);    push(&(env->head), new_item);
312  }  }
313    
 void printerr(const char* in_string) {  
   fprintf(stderr, "Err: %s\n", in_string);  
 }  
   
 /* Throw away a value */  
 void free_val(value *val){  
   stackitem *item, *temp;  
   
   val->refcount--;              /* Decrease the reference count */  
   if(val->refcount == 0){  
     switch (val->type){         /* and free the contents if necessary */  
     case string:  
       free(val->content.ptr);  
       break;  
     case list:                  /* lists needs to be freed recursively */  
       item=val->content.ptr;  
       while(item != NULL) {     /* for all stack items */  
         free_val(item->item);   /* free the value */  
         temp=item->next;        /* save next ptr */  
         free(item);             /* free the stackitem */  
         item=temp;              /* go to next stackitem */  
       }  
       free(val);                /* Free the actual list value */  
       break;  
     default:  
       break;  
     }  
   }  
 }  
   
 /* Discard the top element of the stack. */  
 extern void toss(environment *env)  
 {  
   stackitem *temp= env->head;  
   
   if((env->head)==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
     
   free_val(env->head->item);    /* Free the value */  
   env->head= env->head->next;   /* Remove the top stack item */  
   free(temp);                   /* Free the old top stack item */  
 }  
   
314  /* Print newline. */  /* Print newline. */
315  extern void nl()  extern void nl()
316  {  {
# Line 406  extern void rcl(environment *env) Line 464  extern void rcl(environment *env)
464    push_val(&(env->head), val); /* Return its bound value */    push_val(&(env->head), val); /* Return its bound value */
465  }  }
466    
 extern void pack(environment*);  
467  void stack_read(environment*, char*);  void stack_read(environment*, char*);
468    
   
469  /* If the top element is a symbol, determine if it's bound to a  /* If the top element is a symbol, determine if it's bound to a
470     function value, and if it is, toss the symbol and execute the     function value, and if it is, toss the symbol and execute the
471     function. */     function. */
# Line 418  extern void eval(environment *env) Line 474  extern void eval(environment *env)
474    funcp in_func;    funcp in_func;
475    value* temp_val;    value* temp_val;
476    stackitem* iterator;    stackitem* iterator;
477      char* temp_string;
478    
479    if(env->head==NULL) {    if(env->head==NULL) {
480      printerr("Too Few Arguments");      printerr("Too Few Arguments");
# Line 471  extern void eval(environment *env) Line 528  extern void eval(environment *env)
528      env->head->item->refcount++;      env->head->item->refcount++;
529      toss(env);      toss(env);
530      if(env->err) return;      if(env->err) return;
531      push_sym(env, "[");      temp_string= malloc(strlen((char*)temp_val->content.ptr)+5);
532      env->non_eval_flag++;      strcpy(temp_string, "[ ");
533      stack_read(env, (char*)temp_val->content.ptr);      strcat(temp_string, (char*)temp_val->content.ptr);
534      env->non_eval_flag--;      strcat(temp_string, " ]");
535      push_sym(env, "["); pack(env);      stack_read(env, temp_string);
     if(env->err) return;  
536      eval(env);      eval(env);
537      if(env->err) return;      if(env->err) return;
538      free_val(temp_val);      free_val(temp_val);
539        free(temp_string);
540      break;      break;
541    
542    default:    default:
# Line 842  int main() Line 899  int main()
899    quit(&myenv);    quit(&myenv);
900    return EXIT_FAILURE;    return EXIT_FAILURE;
901  }  }
902    
903    /* + */
904    extern void sx_2b(environment *env) {
905      int a, b;
906      size_t len;
907      char* new_string;
908      value *a_val, *b_val;
909    
910      if((env->head)==NULL || env->head->next==NULL) {
911        printerr("Too Few Arguments");
912        env->err=1;
913        return;
914      }
915    
916      if(env->head->item->type==string
917         && env->head->next->item->type==string) {
918        a_val= env->head->item;
919        b_val= env->head->next->item;
920        a_val->refcount++;
921        b_val->refcount++;
922        toss(env); if(env->err) return;
923        toss(env); if(env->err) return;
924        len= strlen(a_val->content.ptr)+strlen(b_val->content.ptr)+1;
925        new_string= malloc(len);
926        strcpy(new_string, b_val->content.ptr);
927        strcat(new_string, a_val->content.ptr);
928        free_val(a_val); free_val(b_val);
929        push_cstring(&(env->head), new_string);
930        free(new_string);
931        return;
932      }
933      
934      if(env->head->item->type!=integer
935         || env->head->next->item->type!=integer) {
936        printerr("Bad Argument Type");
937        env->err=2;
938        return;
939      }
940      a=env->head->item->content.val;
941      toss(env);
942      if(env->err) return;
943      b=env->head->item->content.val;
944      toss(env);
945      if(env->err) return;
946      push_int(&(env->head), a+b);
947    }
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