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  1. /*
  2. ** $Id: lauxlib.c,v 1.159.1.3 2008/01/21 13:20:51 roberto Exp $
  3. ** Auxiliary functions for building Lua libraries
  4. ** See Copyright Notice in lua.h
  5. */
  6.  
  7.  
  8. #include <ctype.h>
  9. #include <errno.h>
  10. #include <stdarg.h>
  11. #include <stdio.h>
  12. #include <stdlib.h>
  13. #include <string.h>
  14.  
  15.  
  16. /* This file uses only the official API of Lua.
  17. ** Any function declared here could be written as an application function.
  18. */
  19.  
  20. #define lauxlib_c
  21. #define LUA_LIB
  22.  
  23. #include "lua.h"
  24.  
  25. #include "lauxlib.h"
  26.  
  27.  
  28. #define FREELIST_REF    0       /* free list of references */
  29.  
  30.  
  31. /* convert a stack index to positive */
  32. #define abs_index(L, i)         ((i) > 0 || (i) <= LUA_REGISTRYINDEX ? (i) : \
  33.                                         lua_gettop(L) + (i) + 1)
  34.  
  35.  
  36. /*
  37. ** {======================================================
  38. ** Error-report functions
  39. ** =======================================================
  40. */
  41.  
  42.  
  43. LUALIB_API int luaL_argerror (lua_State *L, int narg, const char *extramsg) {
  44.   lua_Debug ar;
  45.   if (!lua_getstack(L, 0, &ar))  /* no stack frame? */
  46.     return luaL_error(L, "bad argument #%d (%s)", narg, extramsg);
  47.   lua_getinfo(L, "n", &ar);
  48.   if (strcmp(ar.namewhat, "method") == 0) {
  49.     narg--;  /* do not count `self' */
  50.     if (narg == 0)  /* error is in the self argument itself? */
  51.       return luaL_error(L, "calling " LUA_QS " on bad self (%s)",
  52.                            ar.name, extramsg);
  53.   }
  54.   if (ar.name == NULL)
  55.     ar.name = "?";
  56.   return luaL_error(L, "bad argument #%d to " LUA_QS " (%s)",
  57.                         narg, ar.name, extramsg);
  58. }
  59.  
  60.  
  61. LUALIB_API int luaL_typerror (lua_State *L, int narg, const char *tname) {
  62.   const char *msg = lua_pushfstring(L, "%s expected, got %s",
  63.                                     tname, luaL_typename(L, narg));
  64.   return luaL_argerror(L, narg, msg);
  65. }
  66.  
  67.  
  68. static void tag_error (lua_State *L, int narg, int tag) {
  69.   luaL_typerror(L, narg, lua_typename(L, tag));
  70. }
  71.  
  72.  
  73. LUALIB_API void luaL_where (lua_State *L, int level) {
  74.   lua_Debug ar;
  75.   if (lua_getstack(L, level, &ar)) {  /* check function at level */
  76.     lua_getinfo(L, "Sl", &ar);  /* get info about it */
  77.     if (ar.currentline > 0) {  /* is there info? */
  78.       lua_pushfstring(L, "%s:%d: ", ar.short_src, ar.currentline);
  79.       return;
  80.     }
  81.   }
  82.   lua_pushliteral(L, "");  /* else, no information available... */
  83. }
  84.  
  85.  
  86. LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) {
  87.   va_list argp;
  88.   va_start(argp, fmt);
  89.   luaL_where(L, 1);
  90.   lua_pushvfstring(L, fmt, argp);
  91.   va_end(argp);
  92.   lua_concat(L, 2);
  93.   return lua_error(L);
  94. }
  95.  
  96. /* }====================================================== */
  97.  
  98.  
  99. LUALIB_API int luaL_checkoption (lua_State *L, int narg, const char *def,
  100.                                  const char *const lst[]) {
  101.   const char *name = (def) ? luaL_optstring(L, narg, def) :
  102.                              luaL_checkstring(L, narg);
  103.   int i;
  104.   for (i=0; lst[i]; i++)
  105.     if (strcmp(lst[i], name) == 0)
  106.       return i;
  107.   return luaL_argerror(L, narg,
  108.                        lua_pushfstring(L, "invalid option " LUA_QS, name));
  109. }
  110.  
  111.  
  112. LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
  113.   lua_getfield(L, LUA_REGISTRYINDEX, tname);  /* get registry.name */
  114.   if (!lua_isnil(L, -1))  /* name already in use? */
  115.     return 0;  /* leave previous value on top, but return 0 */
  116.   lua_pop(L, 1);
  117.   lua_newtable(L);  /* create metatable */
  118.   lua_pushvalue(L, -1);
  119.   lua_setfield(L, LUA_REGISTRYINDEX, tname);  /* registry.name = metatable */
  120.   return 1;
  121. }
  122.  
  123.  
  124. LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
  125.   void *p = lua_touserdata(L, ud);
  126.   if (p != NULL) {  /* value is a userdata? */
  127.     if (lua_getmetatable(L, ud)) {  /* does it have a metatable? */
  128.       lua_getfield(L, LUA_REGISTRYINDEX, tname);  /* get correct metatable */
  129.       if (lua_rawequal(L, -1, -2)) {  /* does it have the correct mt? */
  130.         lua_pop(L, 2);  /* remove both metatables */
  131.         return p;
  132.       }
  133.     }
  134.   }
  135.   luaL_typerror(L, ud, tname);  /* else error */
  136.   return NULL;  /* to avoid warnings */
  137. }
  138.  
  139.  
  140. LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *mes) {
  141.   if (!lua_checkstack(L, space))
  142.     luaL_error(L, "stack overflow (%s)", mes);
  143. }
  144.  
  145.  
  146. LUALIB_API void luaL_checktype (lua_State *L, int narg, int t) {
  147.   if (lua_type(L, narg) != t)
  148.     tag_error(L, narg, t);
  149. }
  150.  
  151.  
  152. LUALIB_API void luaL_checkany (lua_State *L, int narg) {
  153.   if (lua_type(L, narg) == LUA_TNONE)
  154.     luaL_argerror(L, narg, "value expected");
  155. }
  156.  
  157.  
  158. LUALIB_API const char *luaL_checklstring (lua_State *L, int narg, size_t *len) {
  159.   const char *s = lua_tolstring(L, narg, len);
  160.   if (!s) tag_error(L, narg, LUA_TSTRING);
  161.   return s;
  162. }
  163.  
  164.  
  165. LUALIB_API const char *luaL_optlstring (lua_State *L, int narg,
  166.                                         const char *def, size_t *len) {
  167.   if (lua_isnoneornil(L, narg)) {
  168.     if (len)
  169.       *len = (def ? strlen(def) : 0);
  170.     return def;
  171.   }
  172.   else return luaL_checklstring(L, narg, len);
  173. }
  174.  
  175.  
  176. LUALIB_API lua_Number luaL_checknumber (lua_State *L, int narg) {
  177.   lua_Number d = lua_tonumber(L, narg);
  178.   if (d == 0 && !lua_isnumber(L, narg))  /* avoid extra test when d is not 0 */
  179.     tag_error(L, narg, LUA_TNUMBER);
  180.   return d;
  181. }
  182.  
  183.  
  184. LUALIB_API lua_Number luaL_optnumber (lua_State *L, int narg, lua_Number def) {
  185.   return luaL_opt(L, luaL_checknumber, narg, def);
  186. }
  187.  
  188.  
  189. LUALIB_API lua_Integer luaL_checkinteger (lua_State *L, int narg) {
  190.   lua_Integer d = lua_tointeger(L, narg);
  191.   if (d == 0 && !lua_isnumber(L, narg))  /* avoid extra test when d is not 0 */
  192.     tag_error(L, narg, LUA_TNUMBER);
  193.   return d;
  194. }
  195.  
  196.  
  197. LUALIB_API lua_Integer luaL_optinteger (lua_State *L, int narg,
  198.                                                       lua_Integer def) {
  199.   return luaL_opt(L, luaL_checkinteger, narg, def);
  200. }
  201.  
  202.  
  203. LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) {
  204.   if (!lua_getmetatable(L, obj))  /* no metatable? */
  205.     return 0;
  206.   lua_pushstring(L, event);
  207.   lua_rawget(L, -2);
  208.   if (lua_isnil(L, -1)) {
  209.     lua_pop(L, 2);  /* remove metatable and metafield */
  210.     return 0;
  211.   }
  212.   else {
  213.     lua_remove(L, -2);  /* remove only metatable */
  214.     return 1;
  215.   }
  216. }
  217.  
  218.  
  219. LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {
  220.   obj = abs_index(L, obj);
  221.   if (!luaL_getmetafield(L, obj, event))  /* no metafield? */
  222.     return 0;
  223.   lua_pushvalue(L, obj);
  224.   lua_call(L, 1, 1);
  225.   return 1;
  226. }
  227.  
  228.  
  229. LUALIB_API void (luaL_register) (lua_State *L, const char *libname,
  230.                                 const luaL_Reg *l) {
  231.   luaI_openlib(L, libname, l, 0);
  232. }
  233.  
  234.  
  235. static int libsize (const luaL_Reg *l) {
  236.   int size = 0;
  237.   for (; l->name; l++) size++;
  238.   return size;
  239. }
  240.  
  241.  
  242. LUALIB_API void luaI_openlib (lua_State *L, const char *libname,
  243.                               const luaL_Reg *l, int nup) {
  244.   if (libname) {
  245.     int size = libsize(l);
  246.     /* check whether lib already exists */
  247.     luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 1);
  248.     lua_getfield(L, -1, libname);  /* get _LOADED[libname] */
  249.     if (!lua_istable(L, -1)) {  /* not found? */
  250.       lua_pop(L, 1);  /* remove previous result */
  251.       /* try global variable (and create one if it does not exist) */
  252.       if (luaL_findtable(L, LUA_GLOBALSINDEX, libname, size) != NULL)
  253.         luaL_error(L, "name conflict for module " LUA_QS, libname);
  254.       lua_pushvalue(L, -1);
  255.       lua_setfield(L, -3, libname);  /* _LOADED[libname] = new table */
  256.     }
  257.     lua_remove(L, -2);  /* remove _LOADED table */
  258.     lua_insert(L, -(nup+1));  /* move library table to below upvalues */
  259.   }
  260.   for (; l->name; l++) {
  261.     int i;
  262.     for (i=0; i<nup; i++)  /* copy upvalues to the top */
  263.       lua_pushvalue(L, -nup);
  264.     lua_pushcclosure(L, l->func, nup);
  265.     lua_setfield(L, -(nup+2), l->name);
  266.   }
  267.   lua_pop(L, nup);  /* remove upvalues */
  268. }
  269.  
  270.  
  271.  
  272. /*
  273. ** {======================================================
  274. ** getn-setn: size for arrays
  275. ** =======================================================
  276. */
  277.  
  278. #if defined(LUA_COMPAT_GETN)
  279.  
  280. static int checkint (lua_State *L, int topop) {
  281.   int n = (lua_type(L, -1) == LUA_TNUMBER) ? lua_tointeger(L, -1) : -1;
  282.   lua_pop(L, topop);
  283.   return n;
  284. }
  285.  
  286.  
  287. static void getsizes (lua_State *L) {
  288.   lua_getfield(L, LUA_REGISTRYINDEX, "LUA_SIZES");
  289.   if (lua_isnil(L, -1)) {  /* no `size' table? */
  290.     lua_pop(L, 1);  /* remove nil */
  291.     lua_newtable(L);  /* create it */
  292.     lua_pushvalue(L, -1);  /* `size' will be its own metatable */
  293.     lua_setmetatable(L, -2);
  294.     lua_pushliteral(L, "kv");
  295.     lua_setfield(L, -2, "__mode");  /* metatable(N).__mode = "kv" */
  296.     lua_pushvalue(L, -1);
  297.     lua_setfield(L, LUA_REGISTRYINDEX, "LUA_SIZES");  /* store in register */
  298.   }
  299. }
  300.  
  301.  
  302. LUALIB_API void luaL_setn (lua_State *L, int t, int n) {
  303.   t = abs_index(L, t);
  304.   lua_pushliteral(L, "n");
  305.   lua_rawget(L, t);
  306.   if (checkint(L, 1) >= 0) {  /* is there a numeric field `n'? */
  307.     lua_pushliteral(L, "n");  /* use it */
  308.     lua_pushinteger(L, n);
  309.     lua_rawset(L, t);
  310.   }
  311.   else {  /* use `sizes' */
  312.     getsizes(L);
  313.     lua_pushvalue(L, t);
  314.     lua_pushinteger(L, n);
  315.     lua_rawset(L, -3);  /* sizes[t] = n */
  316.     lua_pop(L, 1);  /* remove `sizes' */
  317.   }
  318. }
  319.  
  320.  
  321. LUALIB_API int luaL_getn (lua_State *L, int t) {
  322.   int n;
  323.   t = abs_index(L, t);
  324.   lua_pushliteral(L, "n");  /* try t.n */
  325.   lua_rawget(L, t);
  326.   if ((n = checkint(L, 1)) >= 0) return n;
  327.   getsizes(L);  /* else try sizes[t] */
  328.   lua_pushvalue(L, t);
  329.   lua_rawget(L, -2);
  330.   if ((n = checkint(L, 2)) >= 0) return n;
  331.   return (int)lua_objlen(L, t);
  332. }
  333.  
  334. #endif
  335.  
  336. /* }====================================================== */
  337.  
  338.  
  339.  
  340. LUALIB_API const char *luaL_gsub (lua_State *L, const char *s, const char *p,
  341.                                                                const char *r) {
  342.   const char *wild;
  343.   size_t l = strlen(p);
  344.   luaL_Buffer b;
  345.   luaL_buffinit(L, &b);
  346.   while ((wild = strstr(s, p)) != NULL) {
  347.     luaL_addlstring(&b, s, wild - s);  /* push prefix */
  348.     luaL_addstring(&b, r);  /* push replacement in place of pattern */
  349.     s = wild + l;  /* continue after `p' */
  350.   }
  351.   luaL_addstring(&b, s);  /* push last suffix */
  352.   luaL_pushresult(&b);
  353.   return lua_tostring(L, -1);
  354. }
  355.  
  356.  
  357. LUALIB_API const char *luaL_findtable (lua_State *L, int idx,
  358.                                        const char *fname, int szhint) {
  359.   const char *e;
  360.   lua_pushvalue(L, idx);
  361.   do {
  362.     e = strchr(fname, '.');
  363.     if (e == NULL) e = fname + strlen(fname);
  364.     lua_pushlstring(L, fname, e - fname);
  365.     lua_rawget(L, -2);
  366.     if (lua_isnil(L, -1)) {  /* no such field? */
  367.       lua_pop(L, 1);  /* remove this nil */
  368.       lua_createtable(L, 0, (*e == '.' ? 1 : szhint)); /* new table for field */
  369.       lua_pushlstring(L, fname, e - fname);
  370.       lua_pushvalue(L, -2);
  371.       lua_settable(L, -4);  /* set new table into field */
  372.     }
  373.     else if (!lua_istable(L, -1)) {  /* field has a non-table value? */
  374.       lua_pop(L, 2);  /* remove table and value */
  375.       return fname;  /* return problematic part of the name */
  376.     }
  377.     lua_remove(L, -2);  /* remove previous table */
  378.     fname = e + 1;
  379.   } while (*e == '.');
  380.   return NULL;
  381. }
  382.  
  383.  
  384.  
  385. /*
  386. ** {======================================================
  387. ** Generic Buffer manipulation
  388. ** =======================================================
  389. */
  390.  
  391.  
  392. #define bufflen(B)      ((B)->p - (B)->buffer)
  393. #define bufffree(B)     ((size_t)(LUAL_BUFFERSIZE - bufflen(B)))
  394.  
  395. #define LIMIT   (LUA_MINSTACK/2)
  396.  
  397.  
  398. static int emptybuffer (luaL_Buffer *B) {
  399.   size_t l = bufflen(B);
  400.   if (l == 0) return 0;  /* put nothing on stack */
  401.   else {
  402.     lua_pushlstring(B->L, B->buffer, l);
  403.     B->p = B->buffer;
  404.     B->lvl++;
  405.     return 1;
  406.   }
  407. }
  408.  
  409.  
  410. static void adjuststack (luaL_Buffer *B) {
  411.   if (B->lvl > 1) {
  412.     lua_State *L = B->L;
  413.     int toget = 1;  /* number of levels to concat */
  414.     size_t toplen = lua_strlen(L, -1);
  415.     do {
  416.       size_t l = lua_strlen(L, -(toget+1));
  417.       if (B->lvl - toget + 1 >= LIMIT || toplen > l) {
  418.         toplen += l;
  419.         toget++;
  420.       }
  421.       else break;
  422.     } while (toget < B->lvl);
  423.     lua_concat(L, toget);
  424.     B->lvl = B->lvl - toget + 1;
  425.   }
  426. }
  427.  
  428.  
  429. LUALIB_API char *luaL_prepbuffer (luaL_Buffer *B) {
  430.   if (emptybuffer(B))
  431.     adjuststack(B);
  432.   return B->buffer;
  433. }
  434.  
  435.  
  436. LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) {
  437.   while (l--)
  438.     luaL_addchar(B, *s++);
  439. }
  440.  
  441.  
  442. LUALIB_API void luaL_addstring (luaL_Buffer *B, const char *s) {
  443.   luaL_addlstring(B, s, strlen(s));
  444. }
  445.  
  446.  
  447. LUALIB_API void luaL_pushresult (luaL_Buffer *B) {
  448.   emptybuffer(B);
  449.   lua_concat(B->L, B->lvl);
  450.   B->lvl = 1;
  451. }
  452.  
  453.  
  454. LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
  455.   lua_State *L = B->L;
  456.   size_t vl;
  457.   const char *s = lua_tolstring(L, -1, &vl);
  458.   if (vl <= bufffree(B)) {  /* fit into buffer? */
  459.     memcpy(B->p, s, vl);  /* put it there */
  460.     B->p += vl;
  461.     lua_pop(L, 1);  /* remove from stack */
  462.   }
  463.   else {
  464.     if (emptybuffer(B))
  465.       lua_insert(L, -2);  /* put buffer before new value */
  466.     B->lvl++;  /* add new value into B stack */
  467.     adjuststack(B);
  468.   }
  469. }
  470.  
  471.  
  472. LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
  473.   B->L = L;
  474.   B->p = B->buffer;
  475.   B->lvl = 0;
  476. }
  477.  
  478. /* }====================================================== */
  479.  
  480.  
  481. LUALIB_API int luaL_ref (lua_State *L, int t) {
  482.   int ref;
  483.   t = abs_index(L, t);
  484.   if (lua_isnil(L, -1)) {
  485.     lua_pop(L, 1);  /* remove from stack */
  486.     return LUA_REFNIL;  /* `nil' has a unique fixed reference */
  487.   }
  488.   lua_rawgeti(L, t, FREELIST_REF);  /* get first free element */
  489.   ref = (int)lua_tointeger(L, -1);  /* ref = t[FREELIST_REF] */
  490.   lua_pop(L, 1);  /* remove it from stack */
  491.   if (ref != 0) {  /* any free element? */
  492.     lua_rawgeti(L, t, ref);  /* remove it from list */
  493.     lua_rawseti(L, t, FREELIST_REF);  /* (t[FREELIST_REF] = t[ref]) */
  494.   }
  495.   else {  /* no free elements */
  496.     ref = (int)lua_objlen(L, t);
  497.     ref++;  /* create new reference */
  498.   }
  499.   lua_rawseti(L, t, ref);
  500.   return ref;
  501. }
  502.  
  503.  
  504. LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {
  505.   if (ref >= 0) {
  506.     t = abs_index(L, t);
  507.     lua_rawgeti(L, t, FREELIST_REF);
  508.     lua_rawseti(L, t, ref);  /* t[ref] = t[FREELIST_REF] */
  509.     lua_pushinteger(L, ref);
  510.     lua_rawseti(L, t, FREELIST_REF);  /* t[FREELIST_REF] = ref */
  511.   }
  512. }
  513.  
  514.  
  515.  
  516. /*
  517. ** {======================================================
  518. ** Load functions
  519. ** =======================================================
  520. */
  521.  
  522. typedef struct LoadF {
  523.   int extraline;
  524.   FILE *f;
  525.   char buff[LUAL_BUFFERSIZE];
  526. } LoadF;
  527.  
  528.  
  529. static const char *getF (lua_State *L, void *ud, size_t *size) {
  530.   LoadF *lf = (LoadF *)ud;
  531.   (void)L;
  532.   if (lf->extraline) {
  533.     lf->extraline = 0;
  534.     *size = 1;
  535.     return "\n";
  536.   }
  537.   if (feof(lf->f)) return NULL;
  538.   *size = fread(lf->buff, 1, sizeof(lf->buff), lf->f);
  539.   return (*size > 0) ? lf->buff : NULL;
  540. }
  541.  
  542.  
  543. static int errfile (lua_State *L, const char *what, int fnameindex) {
  544.   const char *serr = strerror(errno);
  545.   const char *filename = lua_tostring(L, fnameindex) + 1;
  546.   lua_pushfstring(L, "cannot %s %s: %s", what, filename, serr);
  547.   lua_remove(L, fnameindex);
  548.   return LUA_ERRFILE;
  549. }
  550.  
  551.  
  552. LUALIB_API int luaL_loadfile (lua_State *L, const char *filename) {
  553.   LoadF lf;
  554.   int status, readstatus;
  555.   int c;
  556.   int fnameindex = lua_gettop(L) + 1;  /* index of filename on the stack */
  557.   lf.extraline = 0;
  558.   if (filename == NULL) {
  559.     lua_pushliteral(L, "=stdin");
  560.     lf.f = stdin;
  561.   }
  562.   else {
  563.     lua_pushfstring(L, "@%s", filename);
  564.     lf.f = fopen(filename, "r");
  565.     if (lf.f == NULL) return errfile(L, "open", fnameindex);
  566.   }
  567.   c = getc(lf.f);
  568.   if (c == '#') {  /* Unix exec. file? */
  569.     lf.extraline = 1;
  570.     while ((c = getc(lf.f)) != EOF && c != '\n') ;  /* skip first line */
  571.     if (c == '\n') c = getc(lf.f);
  572.   }
  573.   if (c == LUA_SIGNATURE[0] && filename) {  /* binary file? */
  574.     lf.f = freopen(filename, "rb", lf.f);  /* reopen in binary mode */
  575.     if (lf.f == NULL) return errfile(L, "reopen", fnameindex);
  576.     /* skip eventual `#!...' */
  577.    while ((c = getc(lf.f)) != EOF && c != LUA_SIGNATURE[0]) ;
  578.     lf.extraline = 0;
  579.   }
  580.   ungetc(c, lf.f);
  581.   status = lua_load(L, getF, &lf, lua_tostring(L, -1));
  582.   readstatus = ferror(lf.f);
  583.   if (filename) fclose(lf.f);  /* close file (even in case of errors) */
  584.   if (readstatus) {
  585.     lua_settop(L, fnameindex);  /* ignore results from `lua_load' */
  586.     return errfile(L, "read", fnameindex);
  587.   }
  588.   lua_remove(L, fnameindex);
  589.   return status;
  590. }
  591.  
  592.  
  593. typedef struct LoadS {
  594.   const char *s;
  595.   size_t size;
  596. } LoadS;
  597.  
  598.  
  599. static const char *getS (lua_State *L, void *ud, size_t *size) {
  600.   LoadS *ls = (LoadS *)ud;
  601.   (void)L;
  602.   if (ls->size == 0) return NULL;
  603.   *size = ls->size;
  604.   ls->size = 0;
  605.   return ls->s;
  606. }
  607.  
  608.  
  609. LUALIB_API int luaL_loadbuffer (lua_State *L, const char *buff, size_t size,
  610.                                 const char *name) {
  611.   LoadS ls;
  612.   ls.s = buff;
  613.   ls.size = size;
  614.   return lua_load(L, getS, &ls, name);
  615. }
  616.  
  617.  
  618. LUALIB_API int (luaL_loadstring) (lua_State *L, const char *s) {
  619.   return luaL_loadbuffer(L, s, strlen(s), s);
  620. }
  621.  
  622.  
  623.  
  624. /* }====================================================== */
  625.  
  626.  
  627. static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
  628.   (void)ud;
  629.   (void)osize;
  630.   if (nsize == 0) {
  631.     free(ptr);
  632.     return NULL;
  633.   }
  634.   else
  635.     return realloc(ptr, nsize);
  636. }
  637.  
  638.  
  639. static int panic (lua_State *L) {
  640.   (void)L;  /* to avoid warnings */
  641.   fprintf(stderr, "PANIC: unprotected error in call to Lua API (%s)\n",
  642.                    lua_tostring(L, -1));
  643.   return 0;
  644. }
  645.  
  646.  
  647. LUALIB_API lua_State *luaL_newstate (void) {
  648.   lua_State *L = lua_newstate(l_alloc, NULL);
  649.   if (L) lua_atpanic(L, &panic);
  650.   return L;
  651. }
  652.  
  653.