src/lapi.c

   1 /*
   2 ** $Id: lapi.c,v 1.110a 2000/10/30 12:50:09 roberto Exp $
   3 ** Lua API
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <string.h>
   9
  10 #include "lua.h"
  11
  12 #include "lapi.h"
  13 #include "ldo.h"
  14 #include "lfunc.h"
  15 #include "lgc.h"
  16 #include "lmem.h"
  17 #include "lobject.h"
  18 #include "lstate.h"
  19 #include "lstring.h"
  20 #include "ltable.h"
  21 #include "ltm.h"
  22 #include "lvm.h"
  23
  24
  25 const char lua_ident[] = "$Lua: " LUA_VERSION " " LUA_COPYRIGHT " $\n"
  26                                "$Authors: " LUA_AUTHORS " $";
  27
  28
  29
  30 #define Index(L,i)      ((i) >= 0 ? (L->Cbase+((i)-1)) : (L->top+(i)))
  31
  32 #define api_incr_top(L) incr_top
  33
  34
  35
  36
  37 TObject *luaA_index (lua_State *L, int index) {
  38   return Index(L, index);
  39 }
  40
  41
  42 static TObject *luaA_indexAcceptable (lua_State *L, int index) {
  43   if (index >= 0) {
  44     TObject *o = L->Cbase+(index-1);
  45     if (o >= L->top) return NULL;
  46     else return o;
  47   }
  48   else return L->top+index;
  49 }
  50
  51
  52 void luaA_pushobject (lua_State *L, const TObject *o) {
  53   *L->top = *o;
  54   incr_top;
  55 }
  56
  57 LUA_API int lua_stackspace (lua_State *L) {
  58   return (L->stack_last - L->top);
  59 }
  60
  61
  62
  63 /*
  64 ** basic stack manipulation
  65 */
  66
  67
  68 LUA_API int lua_gettop (lua_State *L) {
  69   return (L->top - L->Cbase);
  70 }
  71
  72
  73 LUA_API void lua_settop (lua_State *L, int index) {
  74   if (index >= 0)
  75     luaD_adjusttop(L, L->Cbase, index);
  76   else
  77     L->top = L->top+index+1;  /* index is negative */
  78 }
  79
  80
  81 LUA_API void lua_remove (lua_State *L, int index) {
  82   StkId p = luaA_index(L, index);
  83   while (++p < L->top) *(p-1) = *p;
  84   L->top--;
  85 }
  86
  87
  88 LUA_API void lua_insert (lua_State *L, int index) {
  89   StkId p = luaA_index(L, index);
  90   StkId q;
  91   for (q = L->top; q>p; q--)
  92     *q = *(q-1);
  93   *p = *L->top;
  94 }
  95
  96
  97 LUA_API void lua_pushvalue (lua_State *L, int index) {
  98   *L->top = *luaA_index(L, index);
  99   api_incr_top(L);
 100 }
 101
 102
 103
 104 /*
 105 ** access functions (stack -> C)
 106 */
 107
 108
 109 LUA_API int lua_type (lua_State *L, int index) {
 110   StkId o = luaA_indexAcceptable(L, index);
 111   return (o == NULL) ? LUA_TNONE : ttype(o);
 112 }
 113
 114 LUA_API const char *lua_typename (lua_State *L, int t) {
 115   UNUSED(L);
 116   return (t == LUA_TNONE) ? "no value" : luaO_typenames[t];
 117 }
 118
 119
 120 LUA_API int lua_iscfunction (lua_State *L, int index) {
 121   StkId o = luaA_indexAcceptable(L, index);
 122   return (o == NULL) ? 0 : iscfunction(o);
 123 }
 124
 125 LUA_API int lua_isnumber (lua_State *L, int index) {
 126   TObject *o = luaA_indexAcceptable(L, index);
 127   return (o == NULL) ? 0 : (tonumber(o) == 0);
 128 }
 129
 130 LUA_API int lua_isstring (lua_State *L, int index) {
 131   int t = lua_type(L, index);
 132   return (t == LUA_TSTRING || t == LUA_TNUMBER);
 133 }
 134
 135
 136 LUA_API int lua_tag (lua_State *L, int index) {
 137   StkId o = luaA_indexAcceptable(L, index);
 138   return (o == NULL) ? LUA_NOTAG : luaT_tag(o);
 139 }
 140
 141 LUA_API int lua_equal (lua_State *L, int index1, int index2) {
 142   StkId o1 = luaA_indexAcceptable(L, index1);
 143   StkId o2 = luaA_indexAcceptable(L, index2);
 144   if (o1 == NULL || o2 == NULL) return 0;  /* index out-of-range */
 145   else return luaO_equalObj(o1, o2);
 146 }
 147
 148 LUA_API int lua_lessthan (lua_State *L, int index1, int index2) {
 149   StkId o1 = luaA_indexAcceptable(L, index1);
 150   StkId o2 = luaA_indexAcceptable(L, index2);
 151   if (o1 == NULL || o2 == NULL) return 0;  /* index out-of-range */
 152   else return luaV_lessthan(L, o1, o2, L->top);
 153 }
 154
 155
 156
 157 LUA_API double lua_tonumber (lua_State *L, int index) {
 158   StkId o = luaA_indexAcceptable(L, index);
 159   return (o == NULL || tonumber(o)) ? 0 : nvalue(o);
 160 }
 161
 162 LUA_API const char *lua_tostring (lua_State *L, int index) {
 163   StkId o = luaA_indexAcceptable(L, index);
 164   return (o == NULL || tostring(L, o)) ? NULL : svalue(o);
 165 }
 166
 167 LUA_API size_t lua_strlen (lua_State *L, int index) {
 168   StkId o = luaA_indexAcceptable(L, index);
 169   return (o == NULL || tostring(L, o)) ? 0 : tsvalue(o)->len;
 170 }
 171
 172 LUA_API lua_CFunction lua_tocfunction (lua_State *L, int index) {
 173   StkId o = luaA_indexAcceptable(L, index);
 174   return (o == NULL || !iscfunction(o)) ? NULL : clvalue(o)->f.c;
 175 }
 176
 177 LUA_API void *lua_touserdata (lua_State *L, int index) {
 178   StkId o = luaA_indexAcceptable(L, index);
 179   return (o == NULL || ttype(o) != LUA_TUSERDATA) ? NULL :
 180                                                     tsvalue(o)->u.d.value;
 181 }
 182
 183 LUA_API const void *lua_topointer (lua_State *L, int index) {
 184   StkId o = luaA_indexAcceptable(L, index);
 185   if (o == NULL) return NULL;
 186   switch (ttype(o)) {
 187     case LUA_TTABLE:
 188       return hvalue(o);
 189     case LUA_TFUNCTION:
 190       return clvalue(o);
 191     default: return NULL;
 192   }
 193 }
 194
 195
 196
 197 /*
 198 ** push functions (C -> stack)
 199 */
 200
 201
 202 LUA_API void lua_pushnil (lua_State *L) {
 203   ttype(L->top) = LUA_TNIL;
 204   api_incr_top(L);
 205 }
 206
 207
 208 LUA_API void lua_pushnumber (lua_State *L, double n) {
 209   nvalue(L->top) = n;
 210   ttype(L->top) = LUA_TNUMBER;
 211   api_incr_top(L);
 212 }
 213
 214
 215 LUA_API void lua_pushlstring (lua_State *L, const char *s, size_t len) {
 216   tsvalue(L->top) = luaS_newlstr(L, s, len);
 217   ttype(L->top) = LUA_TSTRING;
 218   api_incr_top(L);
 219 }
 220
 221
 222 LUA_API void lua_pushstring (lua_State *L, const char *s) {
 223   if (s == NULL)
 224     lua_pushnil(L);
 225   else
 226     lua_pushlstring(L, s, strlen(s));
 227 }
 228
 229
 230 LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
 231   luaV_Cclosure(L, fn, n);
 232 }
 233
 234
 235 LUA_API void lua_pushusertag (lua_State *L, void *u, int tag) {
 236   /* ORDER LUA_T */
 237   if (!(tag == LUA_ANYTAG || tag == LUA_TUSERDATA || validtag(tag)))
 238     luaO_verror(L, "invalid tag for a userdata (%d)", tag);
 239   tsvalue(L->top) = luaS_createudata(L, u, tag);
 240   ttype(L->top) = LUA_TUSERDATA;
 241   api_incr_top(L);
 242 }
 243
 244
 245
 246 /*
 247 ** get functions (Lua -> stack)
 248 */
 249
 250
 251 LUA_API void lua_getglobal (lua_State *L, const char *name) {
 252   StkId top = L->top;
 253   *top = *luaV_getglobal(L, luaS_new(L, name));
 254   L->top = top;
 255   api_incr_top(L);
 256 }
 257
 258
 259 LUA_API void lua_gettable (lua_State *L, int index) {
 260   StkId t = Index(L, index);
 261   StkId top = L->top;
 262   *(top-1) = *luaV_gettable(L, t);
 263   L->top = top;  /* tag method may change top */
 264 }
 265
 266
 267 LUA_API void lua_rawget (lua_State *L, int index) {
 268   StkId t = Index(L, index);
 269   LUA_ASSERT(ttype(t) == LUA_TTABLE, "table expected");
 270   *(L->top - 1) = *luaH_get(L, hvalue(t), L->top - 1);
 271 }
 272
 273
 274 LUA_API void lua_rawgeti (lua_State *L, int index, int n) {
 275   StkId o = Index(L, index);
 276   LUA_ASSERT(ttype(o) == LUA_TTABLE, "table expected");
 277   *L->top = *luaH_getnum(hvalue(o), n);
 278   api_incr_top(L);
 279 }
 280
 281
 282 LUA_API void lua_getglobals (lua_State *L) {
 283   hvalue(L->top) = L->gt;
 284   ttype(L->top) = LUA_TTABLE;
 285   api_incr_top(L);
 286 }
 287
 288
 289 LUA_API int lua_getref (lua_State *L, int ref) {
 290   if (ref == LUA_REFNIL)
 291     ttype(L->top) = LUA_TNIL;
 292   else if (0 <= ref && ref < L->refSize &&
 293           (L->refArray[ref].st == LOCK || L->refArray[ref].st == HOLD))
 294     *L->top = L->refArray[ref].o;
 295   else
 296     return 0;
 297   api_incr_top(L);
 298   return 1;
 299 }
 300
 301
 302 LUA_API void lua_newtable (lua_State *L) {
 303   hvalue(L->top) = luaH_new(L, 0);
 304   ttype(L->top) = LUA_TTABLE;
 305   api_incr_top(L);
 306 }
 307
 308
 309
 310 /*
 311 ** set functions (stack -> Lua)
 312 */
 313
 314
 315 LUA_API void lua_setglobal (lua_State *L, const char *name) {
 316   StkId top = L->top;
 317   luaV_setglobal(L, luaS_new(L, name));
 318   L->top = top-1;  /* remove element from the top */
 319 }
 320
 321
 322 LUA_API void lua_settable (lua_State *L, int index) {
 323   StkId t = Index(L, index);
 324   StkId top = L->top;
 325   luaV_settable(L, t, top-2);
 326   L->top = top-2;  /* pop index and value */
 327 }
 328
 329
 330 LUA_API void lua_rawset (lua_State *L, int index) {
 331   StkId t = Index(L, index);
 332   LUA_ASSERT(ttype(t) == LUA_TTABLE, "table expected");
 333   *luaH_set(L, hvalue(t), L->top-2) = *(L->top-1);
 334   L->top -= 2;
 335 }
 336
 337
 338 LUA_API void lua_rawseti (lua_State *L, int index, int n) {
 339   StkId o = Index(L, index);
 340   LUA_ASSERT(ttype(o) == LUA_TTABLE, "table expected");
 341   *luaH_setint(L, hvalue(o), n) = *(L->top-1);
 342   L->top--;
 343 }
 344
 345
 346 LUA_API void lua_setglobals (lua_State *L) {
 347   StkId newtable = --L->top;
 348   LUA_ASSERT(ttype(newtable) == LUA_TTABLE, "table expected");
 349   L->gt = hvalue(newtable);
 350 }
 351
 352
 353 LUA_API int lua_ref (lua_State *L,  int lock) {
 354   int ref;
 355   if (ttype(L->top-1) == LUA_TNIL)
 356     ref = LUA_REFNIL;
 357   else {
 358     if (L->refFree != NONEXT) {  /* is there a free place? */
 359       ref = L->refFree;
 360       L->refFree = L->refArray[ref].st;
 361     }
 362     else {  /* no more free places */
 363       luaM_growvector(L, L->refArray, L->refSize, 1, struct Ref,
 364                       "reference table overflow", MAX_INT);
 365       L->nblocks += sizeof(struct Ref);
 366       ref = L->refSize++;
 367     }
 368     L->refArray[ref].o = *(L->top-1);
 369     L->refArray[ref].st = lock ? LOCK : HOLD;
 370   }
 371   L->top--;
 372   return ref;
 373 }
 374
 375
 376 /*
 377 ** "do" functions (run Lua code)
 378 ** (most of them are in ldo.c)
 379 */
 380
 381 LUA_API void lua_rawcall (lua_State *L, int nargs, int nresults) {
 382   luaD_call(L, L->top-(nargs+1), nresults);
 383 }
 384
 385
 386 /*
 387 ** Garbage-collection functions
 388 */
 389
 390 /* GC values are expressed in Kbytes: #bytes/2^10 */
 391 #define GCscale(x)              ((int)((x)>>10))
 392 #define GCunscale(x)            ((unsigned long)(x)<<10)
 393
 394 LUA_API int lua_getgcthreshold (lua_State *L) {
 395   return GCscale(L->GCthreshold);
 396 }
 397
 398 LUA_API int lua_getgccount (lua_State *L) {
 399   return GCscale(L->nblocks);
 400 }
 401
 402 LUA_API void lua_setgcthreshold (lua_State *L, int newthreshold) {
 403   if (newthreshold > GCscale(ULONG_MAX))
 404     L->GCthreshold = ULONG_MAX;
 405   else
 406     L->GCthreshold = GCunscale(newthreshold);
 407   luaC_checkGC(L);
 408 }
 409
 410
 411 /*
 412 ** miscellaneous functions
 413 */
 414
 415 LUA_API void lua_settag (lua_State *L, int tag) {
 416   luaT_realtag(L, tag);
 417   switch (ttype(L->top-1)) {
 418     case LUA_TTABLE:
 419       hvalue(L->top-1)->htag = tag;
 420       break;
 421     case LUA_TUSERDATA:
 422       tsvalue(L->top-1)->u.d.tag = tag;
 423       break;
 424     default:
 425       luaO_verror(L, "cannot change the tag of a %.20s",
 426                   luaO_typename(L->top-1));
 427   }
 428 }
 429
 430
 431 LUA_API void lua_unref (lua_State *L, int ref) {
 432   if (ref >= 0) {
 433     LUA_ASSERT(ref < L->refSize && L->refArray[ref].st < 0, "invalid ref");
 434     L->refArray[ref].st = L->refFree;
 435     L->refFree = ref;
 436   }
 437 }
 438
 439
 440 LUA_API int lua_next (lua_State *L, int index) {
 441   StkId t = luaA_index(L, index);
 442   Node *n;
 443   LUA_ASSERT(ttype(t) == LUA_TTABLE, "table expected");
 444   n = luaH_next(L, hvalue(t), luaA_index(L, -1));
 445   if (n) {
 446     *(L->top-1) = *key(n);
 447     *L->top = *val(n);
 448     api_incr_top(L);
 449     return 1;
 450   }
 451   else {  /* no more elements */
 452     L->top -= 1;  /* remove key */
 453     return 0;
 454   }
 455 }
 456
 457
 458 LUA_API int lua_getn (lua_State *L, int index) {
 459   Hash *h = hvalue(luaA_index(L, index));
 460   const TObject *value = luaH_getstr(h, luaS_new(L, "n"));  /* value = h.n */
 461   if (ttype(value) == LUA_TNUMBER)
 462     return (int)nvalue(value);
 463   else {
 464     Number max = 0;
 465     int i = h->size;
 466     Node *n = h->node;
 467     while (i--) {
 468       if (ttype(key(n)) == LUA_TNUMBER &&
 469           ttype(val(n)) != LUA_TNIL &&
 470           nvalue(key(n)) > max)
 471         max = nvalue(key(n));
 472       n++;
 473     }
 474     return (int)max;
 475   }
 476 }
 477
 478
 479 LUA_API void lua_concat (lua_State *L, int n) {
 480   StkId top = L->top;
 481   luaV_strconc(L, n, top);
 482   L->top = top-(n-1);
 483   luaC_checkGC(L);
 484 }
 485
 486
 487 LUA_API void *lua_newuserdata (lua_State *L, size_t size) {
 488   TString *ts = luaS_newudata(L, (size==0) ? 1 : size, NULL);
 489   tsvalue(L->top) = ts;
 490   ttype(L->top) = LUA_TUSERDATA;
 491   api_incr_top(L);
 492   return ts->u.d.value;
 493 }
 494