| 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 |
/* assert */ |
| 10 |
#include <assert.h> |
| 11 |
|
| 12 |
#define HASHTBLSIZE 65536 |
| 13 |
|
| 14 |
typedef struct stack_item |
| 15 |
{ |
| 16 |
enum { |
| 17 |
value, /* Integer */ |
| 18 |
string, |
| 19 |
ref, /* Reference (to an element in the |
| 20 |
hash table) */ |
| 21 |
func, /* Function pointer */ |
| 22 |
symbol, |
| 23 |
list |
| 24 |
} type; /* Type of stack element */ |
| 25 |
|
| 26 |
union { |
| 27 |
void* ptr; /* Pointer to the content */ |
| 28 |
int val; /* ...or an integer */ |
| 29 |
} content; /* Stores a pointer or an integer */ |
| 30 |
|
| 31 |
char* id; /* Symbol name */ |
| 32 |
struct stack_item* next; /* Next element */ |
| 33 |
} stackitem; |
| 34 |
|
| 35 |
|
| 36 |
typedef stackitem* hashtbl[HASHTBLSIZE]; /* Hash table declaration */ |
| 37 |
typedef void (*funcp)(stackitem**); /* funcp is a pointer to a |
| 38 |
void function (stackitem **) */ |
| 39 |
|
| 40 |
/* Initialize a newly created hash table. */ |
| 41 |
void init_hashtbl(hashtbl out_hash) |
| 42 |
{ |
| 43 |
long i; |
| 44 |
|
| 45 |
for(i= 0; i<HASHTBLSIZE; i++) |
| 46 |
out_hash[i]= NULL; |
| 47 |
} |
| 48 |
|
| 49 |
/* Returns a pointer to an element in the hash table. */ |
| 50 |
stackitem** hash(hashtbl in_hashtbl, const char* in_string) |
| 51 |
{ |
| 52 |
long i= 0; |
| 53 |
unsigned long out_hash= 0; |
| 54 |
char key= '\0'; |
| 55 |
stackitem** position; |
| 56 |
|
| 57 |
while(1){ /* Hash in_string */ |
| 58 |
key= in_string[i++]; |
| 59 |
if(key=='\0') |
| 60 |
break; |
| 61 |
out_hash= out_hash*32+key; |
| 62 |
} |
| 63 |
|
| 64 |
out_hash= out_hash%HASHTBLSIZE; |
| 65 |
position= &(in_hashtbl[out_hash]); |
| 66 |
|
| 67 |
while(1){ |
| 68 |
if(*position==NULL) /* If empty */ |
| 69 |
return position; |
| 70 |
|
| 71 |
if(strcmp(in_string, (*position)->id)==0) /* If match */ |
| 72 |
return position; |
| 73 |
|
| 74 |
position= &((*position)->next); /* Try next */ |
| 75 |
} |
| 76 |
} |
| 77 |
|
| 78 |
/* Generic push function. */ |
| 79 |
int push(stackitem** stack_head, stackitem* in_item) |
| 80 |
{ |
| 81 |
in_item->next= *stack_head; |
| 82 |
*stack_head= in_item; |
| 83 |
return 1; |
| 84 |
} |
| 85 |
|
| 86 |
/* Push a value on the stack. */ |
| 87 |
int push_val(stackitem** stack_head, int in_val) |
| 88 |
{ |
| 89 |
stackitem* new_item= malloc(sizeof(stackitem)); |
| 90 |
assert(new_item != NULL); |
| 91 |
new_item->content.val= in_val; |
| 92 |
new_item->type= value; |
| 93 |
|
| 94 |
push(stack_head, new_item); |
| 95 |
return 1; |
| 96 |
} |
| 97 |
|
| 98 |
/* Copy a string onto the stack. */ |
| 99 |
int push_cstring(stackitem** stack_head, const char* in_string) |
| 100 |
{ |
| 101 |
stackitem* new_item= malloc(sizeof(stackitem)); |
| 102 |
new_item->content.ptr= malloc(strlen(in_string)+1); |
| 103 |
strcpy(new_item->content.ptr, in_string); |
| 104 |
new_item->type= string; |
| 105 |
|
| 106 |
push(stack_head, new_item); |
| 107 |
return 1; |
| 108 |
} |
| 109 |
|
| 110 |
/* Create a new hash entry. */ |
| 111 |
int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id) |
| 112 |
{ |
| 113 |
in_item->id= malloc(strlen(id)+1); |
| 114 |
|
| 115 |
strcpy(in_item->id, id); |
| 116 |
push(hash(in_hashtbl, id), in_item); |
| 117 |
|
| 118 |
return 1; |
| 119 |
} |
| 120 |
|
| 121 |
/* Define a new function in the hash table. */ |
| 122 |
void def_func(hashtbl in_hashtbl, funcp in_func, const char* id) |
| 123 |
{ |
| 124 |
stackitem* temp= malloc(sizeof(stackitem)); |
| 125 |
|
| 126 |
temp->type= func; |
| 127 |
temp->content.ptr= in_func; |
| 128 |
|
| 129 |
mk_hashentry(in_hashtbl, temp, id); |
| 130 |
} |
| 131 |
|
| 132 |
/* Define a new symbol in the hash table. */ |
| 133 |
void def_sym(hashtbl in_hashtbl, const char* id) |
| 134 |
{ |
| 135 |
stackitem* temp= malloc(sizeof(stackitem)); |
| 136 |
|
| 137 |
temp->type= symbol; |
| 138 |
mk_hashentry(in_hashtbl, temp, id); |
| 139 |
} |
| 140 |
|
| 141 |
/* Push a reference to an entry in the hash table onto the stack. */ |
| 142 |
int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string) |
| 143 |
{ |
| 144 |
static void* handle= NULL; |
| 145 |
void* symbol; |
| 146 |
|
| 147 |
stackitem* new_item= malloc(sizeof(stackitem)); |
| 148 |
new_item->content.ptr= *hash(in_hash, in_string); |
| 149 |
new_item->type= ref; |
| 150 |
|
| 151 |
if(new_item->content.ptr==NULL) { /* If hash entry empty */ |
| 152 |
if(handle==NULL) /* If no handle */ |
| 153 |
handle= dlopen(NULL, RTLD_LAZY); |
| 154 |
|
| 155 |
symbol= dlsym(handle, in_string); /* Get function pointer */ |
| 156 |
if(dlerror()==NULL) /* If existing function pointer */ |
| 157 |
def_func(in_hash, symbol, in_string); /* Store function pointer */ |
| 158 |
else |
| 159 |
def_sym(in_hash, in_string); /* Make symbol */ |
| 160 |
|
| 161 |
new_item->content.ptr= *hash(in_hash, in_string); /* The new reference |
| 162 |
shouldn't point at |
| 163 |
NULL */ |
| 164 |
new_item->type= ref; |
| 165 |
} |
| 166 |
|
| 167 |
push(stack_head, new_item); |
| 168 |
return 1; |
| 169 |
} |
| 170 |
|
| 171 |
void printerr(const char* in_string) { |
| 172 |
fprintf(stderr, "Err: %s\n", in_string); |
| 173 |
} |
| 174 |
|
| 175 |
/* Discard the top element of the stack. */ |
| 176 |
extern void toss(stackitem** stack_head) |
| 177 |
{ |
| 178 |
stackitem* temp= *stack_head; |
| 179 |
|
| 180 |
if((*stack_head)==NULL) { |
| 181 |
printerr("Stack empty"); |
| 182 |
return; |
| 183 |
} |
| 184 |
|
| 185 |
if((*stack_head)->type==string) |
| 186 |
free((*stack_head)->content.ptr); |
| 187 |
|
| 188 |
*stack_head= (*stack_head)->next; |
| 189 |
free(temp); |
| 190 |
} |
| 191 |
|
| 192 |
/* Print newline. */ |
| 193 |
extern void nl() |
| 194 |
{ |
| 195 |
printf("\n"); |
| 196 |
} |
| 197 |
|
| 198 |
/* Prints the top element of the stack. */ |
| 199 |
extern void print_(stackitem** stack_head) |
| 200 |
{ |
| 201 |
stackitem* temp= *stack_head; |
| 202 |
|
| 203 |
if(temp==NULL) { |
| 204 |
printerr("Stack empty"); |
| 205 |
return; |
| 206 |
} |
| 207 |
|
| 208 |
while(temp->type==ref) { |
| 209 |
temp= temp->content.ptr; |
| 210 |
|
| 211 |
if(temp->type!=ref) { |
| 212 |
printf("ref-> %s", temp->id); |
| 213 |
return; |
| 214 |
} |
| 215 |
} |
| 216 |
|
| 217 |
switch(temp->type) { |
| 218 |
case value: |
| 219 |
printf("%d", temp->content.val); |
| 220 |
break; |
| 221 |
case string: |
| 222 |
printf("\"%s\"", (char*)temp->content.ptr); |
| 223 |
break; |
| 224 |
case symbol: |
| 225 |
case func: |
| 226 |
printf("%s", temp->id); |
| 227 |
break; |
| 228 |
default: |
| 229 |
printf("%p", temp->content.ptr); |
| 230 |
break; |
| 231 |
} |
| 232 |
} |
| 233 |
|
| 234 |
/* Prints the top element of the stack and then discards it. */ |
| 235 |
extern void print(stackitem** stack_head) |
| 236 |
{ |
| 237 |
print_(stack_head); |
| 238 |
toss(stack_head); |
| 239 |
} |
| 240 |
|
| 241 |
/* Only to be called by function printstack. */ |
| 242 |
void print_st(stackitem* stack_head, long counter) |
| 243 |
{ |
| 244 |
if(stack_head->next != NULL) |
| 245 |
print_st(stack_head->next, counter+1); |
| 246 |
|
| 247 |
printf("%ld: ", counter); |
| 248 |
print_(&stack_head); |
| 249 |
nl(); |
| 250 |
} |
| 251 |
|
| 252 |
/* Prints the stack. */ |
| 253 |
extern void printstack(stackitem** stack_head) |
| 254 |
{ |
| 255 |
if(*stack_head != NULL) { |
| 256 |
print_st(*stack_head, 1); |
| 257 |
nl(); |
| 258 |
} else { |
| 259 |
printerr("Stack empty"); |
| 260 |
} |
| 261 |
} |
| 262 |
|
| 263 |
/* Swap the two top elements on the stack. */ |
| 264 |
extern void swap(stackitem** stack_head) |
| 265 |
{ |
| 266 |
stackitem* temp= (*stack_head); |
| 267 |
|
| 268 |
if((*stack_head)==NULL) { |
| 269 |
printerr("Stack empty"); |
| 270 |
return; |
| 271 |
} |
| 272 |
|
| 273 |
if((*stack_head)->next==NULL) |
| 274 |
return; |
| 275 |
|
| 276 |
*stack_head= (*stack_head)->next; |
| 277 |
temp->next= (*stack_head)->next; |
| 278 |
(*stack_head)->next= temp; |
| 279 |
} |
| 280 |
|
| 281 |
stackitem* copy(stackitem* in_item) |
| 282 |
{ |
| 283 |
stackitem* out_item= malloc(sizeof(stackitem)); |
| 284 |
|
| 285 |
memcpy(out_item, in_item, sizeof(stackitem)); |
| 286 |
out_item->next= NULL; |
| 287 |
|
| 288 |
return out_item; |
| 289 |
} |
| 290 |
|
| 291 |
|
| 292 |
/* If the top element is a reference, determine if it's a reference to a |
| 293 |
function, and if it is, toss the reference and execute the function. */ |
| 294 |
extern void eval(stackitem** stack_head) |
| 295 |
{ |
| 296 |
funcp in_func; |
| 297 |
stackitem* temp= *stack_head; |
| 298 |
|
| 299 |
if(temp==NULL) { |
| 300 |
printerr("Stack empty"); |
| 301 |
return; |
| 302 |
} |
| 303 |
|
| 304 |
while(temp->type==ref) |
| 305 |
temp= temp->content.ptr; |
| 306 |
|
| 307 |
if(temp->type==func) { |
| 308 |
in_func= (funcp)(temp->content.ptr); |
| 309 |
toss(stack_head); |
| 310 |
(*in_func)(stack_head); |
| 311 |
return; |
| 312 |
} |
| 313 |
|
| 314 |
push(stack_head, copy(temp)); |
| 315 |
swap(stack_head); |
| 316 |
toss(stack_head); |
| 317 |
} |
| 318 |
|
| 319 |
/* Make a list. */ |
| 320 |
extern void pack(stackitem** stack_head) |
| 321 |
{ |
| 322 |
void* delimiter; |
| 323 |
stackitem *iterator, *temp, *pack; |
| 324 |
|
| 325 |
delimiter= (*stack_head)->content.ptr; /* Get delimiter */ |
| 326 |
toss(stack_head); |
| 327 |
|
| 328 |
iterator= *stack_head; |
| 329 |
|
| 330 |
if(iterator==NULL || iterator->content.ptr==delimiter) { |
| 331 |
temp= NULL; |
| 332 |
toss(stack_head); |
| 333 |
} else { |
| 334 |
/* Search for first delimiter */ |
| 335 |
while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter) |
| 336 |
iterator= iterator->next; |
| 337 |
|
| 338 |
/* Extract list */ |
| 339 |
temp= *stack_head; |
| 340 |
*stack_head= iterator->next; |
| 341 |
iterator->next= NULL; |
| 342 |
|
| 343 |
if(*stack_head!=NULL && (*stack_head)->content.ptr==delimiter) |
| 344 |
toss(stack_head); |
| 345 |
} |
| 346 |
|
| 347 |
/* Push list */ |
| 348 |
pack= malloc(sizeof(stackitem)); |
| 349 |
pack->type= list; |
| 350 |
pack->content.ptr= temp; |
| 351 |
|
| 352 |
push(stack_head, pack); |
| 353 |
} |
| 354 |
|
| 355 |
/* Parse input. */ |
| 356 |
int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line) |
| 357 |
{ |
| 358 |
char *temp, *rest; |
| 359 |
int itemp; |
| 360 |
size_t inlength= strlen(in_line)+1; |
| 361 |
int convert= 0; |
| 362 |
static int non_eval_flag= 0; |
| 363 |
|
| 364 |
temp= malloc(inlength); |
| 365 |
rest= malloc(inlength); |
| 366 |
|
| 367 |
do { |
| 368 |
/* If string */ |
| 369 |
if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest))) { |
| 370 |
push_cstring(stack_head, temp); |
| 371 |
break; |
| 372 |
} |
| 373 |
/* If value */ |
| 374 |
if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest))) { |
| 375 |
push_val(stack_head, itemp); |
| 376 |
break; |
| 377 |
} |
| 378 |
/* Escape ';' with '\' */ |
| 379 |
if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest))) { |
| 380 |
temp[1]= '\0'; |
| 381 |
push_ref(stack_head, in_hash, temp); |
| 382 |
break; |
| 383 |
} |
| 384 |
/* If symbol */ |
| 385 |
if((convert= sscanf(in_line, "%[^][ ;\n\r]%[^\n\r]", temp, rest))) { |
| 386 |
push_ref(stack_head, in_hash, temp); |
| 387 |
break; |
| 388 |
} |
| 389 |
/* If single char */ |
| 390 |
if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest))) { |
| 391 |
if(*temp==';') { |
| 392 |
if(!non_eval_flag) { |
| 393 |
eval(stack_head); /* Evaluate top element */ |
| 394 |
break; |
| 395 |
} |
| 396 |
|
| 397 |
push_ref(stack_head, in_hash, ";"); |
| 398 |
break; |
| 399 |
} |
| 400 |
|
| 401 |
if(*temp==']') { |
| 402 |
push_ref(stack_head, in_hash, "["); |
| 403 |
pack(stack_head); |
| 404 |
if(non_eval_flag!=0) |
| 405 |
non_eval_flag--; |
| 406 |
break; |
| 407 |
} |
| 408 |
|
| 409 |
if(*temp=='[') { |
| 410 |
push_ref(stack_head, in_hash, "["); |
| 411 |
non_eval_flag++; |
| 412 |
break; |
| 413 |
} |
| 414 |
} |
| 415 |
} while(0); |
| 416 |
|
| 417 |
|
| 418 |
free(temp); |
| 419 |
|
| 420 |
if(convert<2) { |
| 421 |
free(rest); |
| 422 |
return 0; |
| 423 |
} |
| 424 |
|
| 425 |
stack_read(stack_head, in_hash, rest); |
| 426 |
|
| 427 |
free(rest); |
| 428 |
return 1; |
| 429 |
} |
| 430 |
|
| 431 |
/* Relocate elements of the list on the stack. */ |
| 432 |
extern void expand(stackitem** stack_head) |
| 433 |
{ |
| 434 |
stackitem *temp, *new_head; |
| 435 |
|
| 436 |
/* Is top element a list? */ |
| 437 |
if((*stack_head)==NULL || (*stack_head)->type!=list) { |
| 438 |
printerr("Stack empty or not a list"); |
| 439 |
return; |
| 440 |
} |
| 441 |
|
| 442 |
/* The first list element is the new stack head */ |
| 443 |
new_head= temp= (*stack_head)->content.ptr; |
| 444 |
toss(stack_head); |
| 445 |
|
| 446 |
if(temp==NULL) |
| 447 |
return; |
| 448 |
|
| 449 |
/* Search the end of the list */ |
| 450 |
while(temp->next!=NULL) |
| 451 |
temp= temp->next; |
| 452 |
|
| 453 |
/* Connect the the tail of the list with the old stack head */ |
| 454 |
temp->next= *stack_head; |
| 455 |
*stack_head= new_head; /* ...and voila! */ |
| 456 |
} |
| 457 |
|
| 458 |
/* Compares two elements by reference. */ |
| 459 |
extern void eq(stackitem** stack_head) |
| 460 |
{ |
| 461 |
void *left, *right; |
| 462 |
int result; |
| 463 |
|
| 464 |
if((*stack_head)==NULL || (*stack_head)->next==NULL) { |
| 465 |
printerr("Not enough elements to compare"); |
| 466 |
return; |
| 467 |
} |
| 468 |
|
| 469 |
left= (*stack_head)->content.ptr; |
| 470 |
swap(stack_head); |
| 471 |
right= (*stack_head)->content.ptr; |
| 472 |
result= (left==right); |
| 473 |
|
| 474 |
toss(stack_head); toss(stack_head); |
| 475 |
push_val(stack_head, (left==right)); |
| 476 |
} |
| 477 |
|
| 478 |
/* Negates the top element on the stack. */ |
| 479 |
extern void not(stackitem** stack_head) |
| 480 |
{ |
| 481 |
int value; |
| 482 |
|
| 483 |
if((*stack_head)==NULL || (*stack_head)->type!=value) { |
| 484 |
printerr("Stack empty or element is not a value"); |
| 485 |
return; |
| 486 |
} |
| 487 |
|
| 488 |
value= (*stack_head)->content.val; |
| 489 |
toss(stack_head); |
| 490 |
push_val(stack_head, !value); |
| 491 |
} |
| 492 |
|
| 493 |
/* Compares the two top elements on the stack and return 0 if they're the |
| 494 |
same. */ |
| 495 |
extern void neq(stackitem** stack_head) |
| 496 |
{ |
| 497 |
eq(stack_head); |
| 498 |
not(stack_head); |
| 499 |
} |
| 500 |
|
| 501 |
/* Give a symbol some content. */ |
| 502 |
extern void def(stackitem** stack_head) |
| 503 |
{ |
| 504 |
stackitem *temp, *value; |
| 505 |
|
| 506 |
if(*stack_head==NULL || (*stack_head)->next==NULL |
| 507 |
|| (*stack_head)->type!=ref) { |
| 508 |
printerr("Define what?"); |
| 509 |
return; |
| 510 |
} |
| 511 |
|
| 512 |
temp= (*stack_head)->content.ptr; |
| 513 |
value= (*stack_head)->next; |
| 514 |
temp->content= value->content; |
| 515 |
value->content.ptr=NULL; |
| 516 |
temp->type= value->type; |
| 517 |
|
| 518 |
toss(stack_head); toss(stack_head); |
| 519 |
} |
| 520 |
|
| 521 |
/* Quit stack. */ |
| 522 |
extern void quit() |
| 523 |
{ |
| 524 |
exit(EXIT_SUCCESS); |
| 525 |
} |
| 526 |
|
| 527 |
/* Clear stack */ |
| 528 |
extern void clear(stackitem** stack_head) |
| 529 |
{ |
| 530 |
while(*stack_head!=NULL) |
| 531 |
toss(stack_head); |
| 532 |
} |
| 533 |
|
| 534 |
int main() |
| 535 |
{ |
| 536 |
stackitem* s= NULL; |
| 537 |
hashtbl myhash; |
| 538 |
char in_string[100]; |
| 539 |
|
| 540 |
init_hashtbl(myhash); |
| 541 |
|
| 542 |
printf("okidok\n "); |
| 543 |
|
| 544 |
while(fgets(in_string, 100, stdin) != NULL) { |
| 545 |
stack_read(&s, myhash, in_string); |
| 546 |
printf("okidok\n "); |
| 547 |
} |
| 548 |
|
| 549 |
exit(EXIT_SUCCESS); |
| 550 |
} |
| 551 |
|
| 552 |
/* Local Variables: */ |
| 553 |
/* compile-command:"make CFLAGS=\"-Wall -g -rdynamic -ldl\" stack" */ |
| 554 |
/* End: */ |
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