cvs/stack/stack.c

/* printf */
#include <stdio.h>
/* EXIT_SUCCESS */
#include <stdlib.h>
/* NULL */
#include <stddef.h>
/* dlopen, dlsym, dlerror */
#include <dlfcn.h>

#define HASHTBLSIZE 65536

typedef struct stack_item
{
  enum {value, string, ref, func, symbol, list} type;
  union {
    void* ptr;
    int val;
  } content;

  char* id;
  struct stack_item* next;
} stackitem;


typedef stackitem* hashtbl[HASHTBLSIZE];
typedef void (*funcp)(stackitem**);


/* Initiates a newly created hash table. */
void init_hashtbl(hashtbl out_hash)
{
  long i;

  for(i= 0; i<HASHTBLSIZE; i++)
    out_hash[i]= NULL;
}

/* Returns a pointer to an element in the hash table. */
stackitem** hash(hashtbl in_hashtbl, const char* in_string)
{
  long i= 0;
  unsigned long out_hash= 0;
  char key= 0;
  stackitem** position;
  
  while(1){
    key= in_string[i++];
    if(key=='\0')
      break;
    out_hash= out_hash*32+key;
  }

  out_hash= out_hash%HASHTBLSIZE;
  position= &(in_hashtbl[out_hash]);

  while(1){
    if(*position==NULL)
      return position;
    
    if(strcmp(in_string, (*position)->id)==0)
      return position;

    position= &((*position)->next);
  }
}

/* Generic push function. */
int push(stackitem** stack_head, stackitem* in_item)
{
  in_item->next= *stack_head;
  *stack_head= in_item;
  return 1;
}

/* Push a value on the stack. */
int push_val(stackitem** stack_head, int in_val) 
{
  stackitem* new_item= malloc(sizeof(stackitem));
  new_item->content.val= in_val;
  new_item->type= value;

  push(stack_head, new_item);
  return 1;
}

/* Copy a string onto the stack. */
int push_cstring(stackitem** stack_head, const char* in_string)
{
  stackitem* new_item= malloc(sizeof(stackitem));
  new_item->content.ptr= malloc(strlen(in_string)+1);
  strcpy(new_item->content.ptr, in_string);
  new_item->type= string;

  push(stack_head, new_item);
  return 1;
}

/* Create a new hash entry. */
int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id)
{
  in_item->id= malloc(strlen(id)+1);

  strcpy(in_item->id, id);
  push(hash(in_hashtbl, id), in_item);

  return 1;
}

/* Define a function a new function in the hash table. */
void def_func(hashtbl in_hashtbl, funcp in_func, const char* id)
{
  stackitem* temp= malloc(sizeof(stackitem));

  temp->type= func;
  temp->content.ptr= in_func;

  mk_hashentry(in_hashtbl, temp, id);
}

/* Define a new symbol in the hash table. */
void def_sym(hashtbl in_hashtbl, const char* id)
{
  stackitem* temp= malloc(sizeof(stackitem));
  
  temp->type= symbol;

  mk_hashentry(in_hashtbl, temp, id);
}

/* Push a reference to an entry in the hash table onto the stack. */
int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string)
{
  static void* handle= NULL;
  void* symbol;

  stackitem* new_item= malloc(sizeof(stackitem));
  new_item->content.ptr= *hash(in_hash, in_string);
  new_item->type= ref;

  if(new_item->content.ptr==NULL) {
    if(handle==NULL)
      handle= dlopen(NULL, RTLD_LAZY);    

    symbol= dlsym(handle, in_string);
    if(dlerror()==NULL) 
      def_func(in_hash, symbol, in_string);
    else
      def_sym(in_hash, in_string);
      
    new_item->content.ptr= *hash(in_hash, in_string);
    new_item->type= ref;
  }

  push(stack_head, new_item);
  return 1;
}

/* Discard the top element of the stack. */
extern void toss(stackitem** stack_head)
{
  stackitem* temp= *stack_head;

  if((*stack_head)==NULL)
    return;
  
  if((*stack_head)->type==string)
    free((*stack_head)->content.ptr);

  *stack_head= (*stack_head)->next;
  free(temp);
}

/* Print newline. */
extern void nl()
{
  printf("\n");
}

/* Prints the top element of the stack. */
void print_(stackitem** stack_head)
{
  if((*stack_head)==NULL)
    return;

  switch((*stack_head)->type) {
  case value:
    printf("%d", (*stack_head)->content.val);
    break;
  case string:
    printf("%s", (char*)(*stack_head)->content.ptr);
    break;
  case ref:
    printf("%s", ((stackitem*)(*stack_head)->content.ptr)->id);
    break;
  case symbol:
  default:
    printf("%p", (*stack_head)->content.ptr);
    break;
  }
}

/* Prints the top element of the stack and then discards it. */
extern void print(stackitem** stack_head)
{
  print_(stack_head);
  toss(stack_head);
}

/* Only to be called by function printstack. */
void print_st(stackitem* stack_head, long counter)
{ 
  if(stack_head->next != NULL)
    print_st(stack_head->next, counter+1);

  printf("%ld: ", counter);
  print_(&stack_head);
  nl();
}

/* Prints the stack. */
extern void printstack(stackitem** stack_head)
{
  if(*stack_head != NULL) {
    print_st(*stack_head, 1);
    printf("\n");
  }
}

/* If the top element is a reference, determine if it's a reference to a
   function, and if it is execute and pop the reference and execute the
   function. */
extern void eval(stackitem** stack_head)
{
  funcp in_func;

  if((*stack_head)==NULL || (*stack_head)->type!=ref)
    return;

  if(((stackitem*)(*stack_head)->content.ptr)->type==func) {
    in_func= (funcp)((stackitem*)(*stack_head)->content.ptr)->content.ptr;
    toss(stack_head); 
    (*in_func)(stack_head);
    return;
  }
}

/* Parse input. */
int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line) 
{
  char *temp, *rest;
  int itemp;
  size_t inlength= strlen(in_line)+1;
  int convert= 0;

  temp= malloc(inlength);
  rest= malloc(inlength);

  if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest)) >= 1)
    push_cstring(stack_head, temp);
  else if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest)) >= 1)
    push_val(stack_head, itemp);
  else if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest)) >= 1) {
    temp[1]= '\0'; push_ref(stack_head, in_hash, temp);
  } else if((convert= sscanf(in_line, "%[^ ;\n\r]%[^\n\r]", temp, rest)) >= 1) 
    push_ref(stack_head, in_hash, temp);
  else if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest)) >= 1)
    if(*temp==';')
      eval(stack_head);

  free(temp);

  if(convert<2) {
    free(rest);
    return 0;
  }
   
  stack_read(stack_head, in_hash, rest);
  
  free(rest);
  return 1;
}

/* Make a list. */
extern void pack(stackitem** stack_head)
{
  void* delimiter;
  stackitem *iterator, *temp, *pack;

  if((*stack_head)==NULL)
    return;

  delimiter= (*stack_head)->content.ptr;
  toss(stack_head);

  iterator= *stack_head;

  while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter)
    iterator= iterator->next;

  temp= *stack_head;
  *stack_head= iterator->next;
  iterator->next= NULL;
  
  if(*stack_head!=NULL && (*stack_head)->content.ptr==delimiter)
    toss(stack_head);

  pack= malloc(sizeof(stackitem));
  pack->type= list;
  pack->content.ptr= temp;

  push(stack_head, pack);
}

/* Push elements of the list on the stack. */
extern void expand(stackitem** stack_head)
{
  stackitem *temp, *new_head;

  if((*stack_head)==NULL || (*stack_head)->type!=list)
    return;

  new_head= temp= (*stack_head)->content.ptr;
  toss(stack_head);

  while(temp->next!=NULL)
    temp= temp->next;

  temp->next= *stack_head;
  *stack_head= new_head;
}

/* Swap the two top elements on the stack. */
extern void swap(stackitem** stack_head)
{
  stackitem* temp= (*stack_head);
  
  if((*stack_head)==NULL || (*stack_head)->next==NULL)
    return;

  *stack_head= (*stack_head)->next;
  temp->next= (*stack_head)->next;
  (*stack_head)->next= temp;
} 

/* Compares two elements by reference. */
extern void eq(stackitem** stack_head)
{
  void *left, *right;
  int result;

  if((*stack_head)==NULL || (*stack_head)->next==NULL)
    return;

  left= (*stack_head)->content.ptr;
  swap(stack_head);
  right= (*stack_head)->content.ptr;
  result= (left==right);
  
  toss(stack_head); toss(stack_head);
  push_val(stack_head, (left==right));
}

/* Negates the top element on the stack. */
extern void not(stackitem** stack_head)
{
  int value;

  if((*stack_head)==NULL)
    return;

  value= (*stack_head)->content.val;
  toss(stack_head);
  push_val(stack_head, !value);
}

/* Compares the two top elements on the stack and return 0 if they're the
   same. */
extern void neq(stackitem** stack_head)
{
  eq(stack_head);
  not(stack_head);
}

/* Give a symbol some content. */
extern void def(stackitem** stack_head)
{
  stackitem *temp, *value;

  if(*stack_head==NULL || (*stack_head)->next==NULL 
     || (*stack_head)->type!=ref)
    return;

  temp= (*stack_head)->content.ptr;
  value= (*stack_head)->next;
  temp->content= value->content;
  value->content.ptr=NULL;
  temp->type= value->type;

  toss(stack_head); toss(stack_head);
} 

/* Quit stack. */
extern void quit()
{
  exit(EXIT_SUCCESS);
}

int main()
{
  stackitem* s= NULL;
  hashtbl myhash;
  char in_string[100];

  init_hashtbl(myhash);

  printf("okidok\n ");

  while(fgets(in_string, 100, stdin) != NULL) {
    stack_read(&s, myhash, in_string);
    printf("okidok\n ");
  }

  exit(EXIT_SUCCESS);
}

/* Local Variables: */
/* compile-command:"make CFLAGS=\"-Wall -g -rdynamic -ldl\" stack" */
/* End: */
1	/* printf */
2	#include <stdio.h>
3	/* EXIT_SUCCESS */
4	#include <stdlib.h>
5	/* NULL */
6	#include <stddef.h>
7	/* dlopen, dlsym, dlerror */
8	#include <dlfcn.h>
9
10	#define HASHTBLSIZE 65536
11
12	typedef struct stack_item
13	{
14	enum {value, string, ref, func, symbol, list} type;
15	union {
16	void* ptr;
17	int val;
18	} content;
19
20	char* id;
21	struct stack_item* next;
22	} stackitem;
23
24
25	typedef stackitem* hashtbl[HASHTBLSIZE];
26	typedef void (funcp)(stackitem*);
27
28
29	/* Initiates a newly created hash table. */
30	void init_hashtbl(hashtbl out_hash)
31	{
32	long i;
33
34	for(i= 0; i<HASHTBLSIZE; i++)
35	out_hash[i]= NULL;
36	}
37
38	/* Returns a pointer to an element in the hash table. */
39	stackitem** hash(hashtbl in_hashtbl, const char* in_string)
40	{
41	long i= 0;
42	unsigned long out_hash= 0;
43	char key= 0;
44	stackitem** position;
45
46	while(1){
47	key= in_string[i++];
48	if(key=='\0')
49	break;
50	out_hash= out_hash*32+key;
51	}
52
53	out_hash= out_hash%HASHTBLSIZE;
54	position= &(in_hashtbl[out_hash]);
55
56	while(1){
57	if(*position==NULL)
58	return position;
59
60	if(strcmp(in_string, (*position)->id)==0)
61	return position;
62
63	position= &((*position)->next);
64	}
65	}
66
67	/* Generic push function. */
68	int push(stackitem** stack_head, stackitem* in_item)
69	{
70	in_item->next= *stack_head;
71	*stack_head= in_item;
72	return 1;
73	}
74
75	/* Push a value on the stack. */
76	int push_val(stackitem** stack_head, int in_val)
77	{
78	stackitem* new_item= malloc(sizeof(stackitem));
79	new_item->content.val= in_val;
80	new_item->type= value;
81
82	push(stack_head, new_item);
83	return 1;
84	}
85
86	/* Copy a string onto the stack. */
87	int push_cstring(stackitem** stack_head, const char* in_string)
88	{
89	stackitem* new_item= malloc(sizeof(stackitem));
90	new_item->content.ptr= malloc(strlen(in_string)+1);
91	strcpy(new_item->content.ptr, in_string);
92	new_item->type= string;
93
94	push(stack_head, new_item);
95	return 1;
96	}
97
98	/* Create a new hash entry. */
99	int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id)
100	{
101	in_item->id= malloc(strlen(id)+1);
102
103	strcpy(in_item->id, id);
104	push(hash(in_hashtbl, id), in_item);
105
106	return 1;
107	}
108
109	/* Define a function a new function in the hash table. */
110	void def_func(hashtbl in_hashtbl, funcp in_func, const char* id)
111	{
112	stackitem* temp= malloc(sizeof(stackitem));
113
114	temp->type= func;
115	temp->content.ptr= in_func;
116
117	mk_hashentry(in_hashtbl, temp, id);
118	}
119
120	/* Define a new symbol in the hash table. */
121	void def_sym(hashtbl in_hashtbl, const char* id)
122	{
123	stackitem* temp= malloc(sizeof(stackitem));
124
125	temp->type= symbol;
126
127	mk_hashentry(in_hashtbl, temp, id);
128	}
129
130	/* Push a reference to an entry in the hash table onto the stack. */
131	int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string)
132	{
133	static void* handle= NULL;
134	void* symbol;
135
136	stackitem* new_item= malloc(sizeof(stackitem));
137	new_item->content.ptr= *hash(in_hash, in_string);
138	new_item->type= ref;
139
140	if(new_item->content.ptr==NULL) {
141	if(handle==NULL)
142	handle= dlopen(NULL, RTLD_LAZY);
143
144	symbol= dlsym(handle, in_string);
145	if(dlerror()==NULL)
146	def_func(in_hash, symbol, in_string);
147	else
148	def_sym(in_hash, in_string);
149
150	new_item->content.ptr= *hash(in_hash, in_string);
151	new_item->type= ref;
152	}
153
154	push(stack_head, new_item);
155	return 1;
156	}
157
158	/* Discard the top element of the stack. */
159	extern void toss(stackitem** stack_head)
160	{
161	stackitem* temp= *stack_head;
162
163	if((*stack_head)==NULL)
164	return;
165
166	if((*stack_head)->type==string)
167	free((*stack_head)->content.ptr);
168
169	stack_head= (stack_head)->next;
170	free(temp);
171	}
172
173	/* Print newline. */
174	extern void nl()
175	{
176	printf("\n");
177	}
178
179	/* Prints the top element of the stack. */
180	void print_(stackitem** stack_head)
181	{
182	if((*stack_head)==NULL)
183	return;
184
185	switch((*stack_head)->type) {
186	case value:
187	printf("%d", (*stack_head)->content.val);
188	break;
189	case string:
190	printf("%s", (char)(stack_head)->content.ptr);
191	break;
192	case ref:
193	printf("%s", ((stackitem)(stack_head)->content.ptr)->id);
194	break;
195	case symbol:
196	default:
197	printf("%p", (*stack_head)->content.ptr);
198	break;
199	}
200	}
201
202	/* Prints the top element of the stack and then discards it. */
203	extern void print(stackitem** stack_head)
204	{
205	print_(stack_head);
206	toss(stack_head);
207	}
208
209	/* Only to be called by function printstack. */
210	void print_st(stackitem* stack_head, long counter)
211	{
212	if(stack_head->next != NULL)
213	print_st(stack_head->next, counter+1);
214
215	printf("%ld: ", counter);
216	print_(&stack_head);
217	nl();
218	}
219
220	/* Prints the stack. */
221	extern void printstack(stackitem** stack_head)
222	{
223	if(*stack_head != NULL) {
224	print_st(*stack_head, 1);
225	printf("\n");
226	}
227	}
228
229	/* If the top element is a reference, determine if it's a reference to a
230	function, and if it is execute and pop the reference and execute the
231	function. */
232	extern void eval(stackitem** stack_head)
233	{
234	funcp in_func;
235
236	if((stack_head)==NULL \|\| (stack_head)->type!=ref)
237	return;
238
239	if(((stackitem)(stack_head)->content.ptr)->type==func) {
240	in_func= (funcp)((stackitem)(stack_head)->content.ptr)->content.ptr;
241	toss(stack_head);
242	(*in_func)(stack_head);
243	return;
244	}
245	}
246
247	/* Parse input. */
248	int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line)
249	{
250	char temp, rest;
251	int itemp;
252	size_t inlength= strlen(in_line)+1;
253	int convert= 0;
254
255	temp= malloc(inlength);
256	rest= malloc(inlength);
257
258	if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest)) >= 1)
259	push_cstring(stack_head, temp);
260	else if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest)) >= 1)
261	push_val(stack_head, itemp);
262	else if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest)) >= 1) {
263	temp[1]= '\0'; push_ref(stack_head, in_hash, temp);
264	} else if((convert= sscanf(in_line, "%[^ ;\n\r]%[^\n\r]", temp, rest)) >= 1)
265	push_ref(stack_head, in_hash, temp);
266	else if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest)) >= 1)
267	if(*temp==';')
268	eval(stack_head);
269
270	free(temp);
271
272	if(convert<2) {
273	free(rest);
274	return 0;
275	}
276
277	stack_read(stack_head, in_hash, rest);
278
279	free(rest);
280	return 1;
281	}
282
283	/* Make a list. */
284	extern void pack(stackitem** stack_head)
285	{
286	void* delimiter;
287	stackitem iterator, temp, *pack;
288
289	if((*stack_head)==NULL)
290	return;
291
292	delimiter= (*stack_head)->content.ptr;
293	toss(stack_head);
294
295	iterator= *stack_head;
296
297	while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter)
298	iterator= iterator->next;
299
300	temp= *stack_head;
301	*stack_head= iterator->next;
302	iterator->next= NULL;
303
304	if(stack_head!=NULL && (stack_head)->content.ptr==delimiter)
305	toss(stack_head);
306
307	pack= malloc(sizeof(stackitem));
308	pack->type= list;
309	pack->content.ptr= temp;
310
311	push(stack_head, pack);
312	}
313
314	/* Push elements of the list on the stack. */
315	extern void expand(stackitem** stack_head)
316	{
317	stackitem temp, new_head;
318
319	if((stack_head)==NULL \|\| (stack_head)->type!=list)
320	return;
321
322	new_head= temp= (*stack_head)->content.ptr;
323	toss(stack_head);
324
325	while(temp->next!=NULL)
326	temp= temp->next;
327
328	temp->next= *stack_head;
329	*stack_head= new_head;
330	}
331
332	/* Swap the two top elements on the stack. */
333	extern void swap(stackitem** stack_head)
334	{
335	stackitem* temp= (*stack_head);
336
337	if((stack_head)==NULL \|\| (stack_head)->next==NULL)
338	return;
339
340	stack_head= (stack_head)->next;
341	temp->next= (*stack_head)->next;
342	(*stack_head)->next= temp;
343	}
344
345	/* Compares two elements by reference. */
346	extern void eq(stackitem** stack_head)
347	{
348	void left, right;
349	int result;
350
351	if((stack_head)==NULL \|\| (stack_head)->next==NULL)
352	return;
353
354	left= (*stack_head)->content.ptr;
355	swap(stack_head);
356	right= (*stack_head)->content.ptr;
357	result= (left==right);
358
359	toss(stack_head); toss(stack_head);
360	push_val(stack_head, (left==right));
361	}
362
363	/* Negates the top element on the stack. */
364	extern void not(stackitem** stack_head)
365	{
366	int value;
367
368	if((*stack_head)==NULL)
369	return;
370
371	value= (*stack_head)->content.val;
372	toss(stack_head);
373	push_val(stack_head, !value);
374	}
375
376	/* Compares the two top elements on the stack and return 0 if they're the
377	same. */
378	extern void neq(stackitem** stack_head)
379	{
380	eq(stack_head);
381	not(stack_head);
382	}
383
384	/* Give a symbol some content. */
385	extern void def(stackitem** stack_head)
386	{
387	stackitem temp, value;
388
389	if(stack_head==NULL \|\| (stack_head)->next==NULL
390	\|\| (*stack_head)->type!=ref)
391	return;
392
393	temp= (*stack_head)->content.ptr;
394	value= (*stack_head)->next;
395	temp->content= value->content;
396	value->content.ptr=NULL;
397	temp->type= value->type;
398
399	toss(stack_head); toss(stack_head);
400	}
401
402	/* Quit stack. */
403	extern void quit()
404	{
405	exit(EXIT_SUCCESS);
406	}
407
408	int main()
409	{
410	stackitem* s= NULL;
411	hashtbl myhash;
412	char in_string[100];
413
414	init_hashtbl(myhash);
415
416	printf("okidok\n ");
417
418	while(fgets(in_string, 100, stdin) != NULL) {
419	stack_read(&s, myhash, in_string);
420	printf("okidok\n ");
421	}
422
423	exit(EXIT_SUCCESS);
424	}
425
426	/* Local Variables: */
427	/* compile-command:"make CFLAGS=\"-Wall -g -rdynamic -ldl\" stack" */
428	/* End: */