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/*** $Id: lstate.c,v 2.98 2012/05/30 12:33:44 roberto Exp $** Global State** See Copyright Notice in lua.h*/  #include <stddef.h>#include <string.h> #define lstate_c#define LUA_CORE #include "lua.h" #include "lapi.h"#include "ldebug.h"#include "ldo.h"#include "lfunc.h"#include "lgc.h"#include "llex.h"#include "lmem.h"#include "lstate.h"#include "lstring.h"#include "ltable.h"#include "ltm.h"  #if !defined(LUAI_GCPAUSE)#define LUAI_GCPAUSE	200  /* 200% */#endif #if !defined(LUAI_GCMAJOR)#define LUAI_GCMAJOR	200  /* 200% */#endif #if !defined(LUAI_GCMUL)#define LUAI_GCMUL	200 /* GC runs 'twice the speed' of memory allocation */#endif  #define MEMERRMSG	"not enough memory"  /*** a macro to help the creation of a unique random seed when a state is** created; the seed is used to randomize hashes.*/#if !defined(luai_makeseed)#include <time.h>#define luai_makeseed()		cast(size_t, time(NULL))#endif   /*** thread state + extra space*/typedef struct LX {#if defined(LUAI_EXTRASPACE)  char buff[LUAI_EXTRASPACE];#endif  lua_State l;} LX;  /*** Main thread combines a thread state and the global state*/typedef struct LG {  LX l;  global_State g;} LG;   #define fromstate(L)	(cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l)))  /*** Compute an initial seed as random as possible. In ANSI, rely on** Address Space Layout Randomization (if present) to increase** randomness..*/#define addbuff(b,p,e) \  { size_t t = cast(size_t, e); \    memcpy(buff + p, &t, sizeof(t)); p += sizeof(t); } static unsigned int makeseed (lua_State *L) {  char buff[4 * sizeof(size_t)];  unsigned int h = luai_makeseed();  int p = 0;  addbuff(buff, p, L);  /* heap variable */  addbuff(buff, p, &h);  /* local variable */  addbuff(buff, p, luaO_nilobject);  /* global variable */  addbuff(buff, p, &lua_newstate);  /* public function */  lua_assert(p == sizeof(buff));  return luaS_hash(buff, p, h);}  /*** set GCdebt to a new value keeping the value (totalbytes + GCdebt)** invariant*/void luaE_setdebt (global_State *g, l_mem debt) {  g->totalbytes -= (debt - g->GCdebt);  g->GCdebt = debt;}  CallInfo *luaE_extendCI (lua_State *L) {  CallInfo *ci = luaM_new(L, CallInfo);  lua_assert(L->ci->next == NULL);  L->ci->next = ci;  ci->previous = L->ci;  ci->next = NULL;  return ci;}  void luaE_freeCI (lua_State *L) {  CallInfo *ci = L->ci;  CallInfo *next = ci->next;  ci->next = NULL;  while ((ci = next) != NULL) {    next = ci->next;    luaM_free(L, ci);  }}  static void stack_init (lua_State *L1, lua_State *L) {  int i; CallInfo *ci;  /* initialize stack array */  L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);  L1->stacksize = BASIC_STACK_SIZE;  for (i = 0; i < BASIC_STACK_SIZE; i++)    setnilvalue(L1->stack + i);  /* erase new stack */  L1->top = L1->stack;  L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;  /* initialize first ci */  ci = &L1->base_ci;  ci->next = ci->previous = NULL;  ci->callstatus = 0;  ci->func = L1->top;  setnilvalue(L1->top++);  /* 'function' entry for this 'ci' */  ci->top = L1->top + LUA_MINSTACK;  L1->ci = ci;}  static void freestack (lua_State *L) {  if (L->stack == NULL)    return;  /* stack not completely built yet */  L->ci = &L->base_ci;  /* free the entire 'ci' list */  luaE_freeCI(L);  luaM_freearray(L, L->stack, L->stacksize);  /* free stack array */}  /*** Create registry table and its predefined values*/static void init_registry (lua_State *L, global_State *g) {  TValue mt;  /* create registry */  Table *registry = luaH_new(L);  sethvalue(L, &g->l_registry, registry);  luaH_resize(L, registry, LUA_RIDX_LAST, 0);  /* registry[LUA_RIDX_MAINTHREAD] = L */  setthvalue(L, &mt, L);  luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &mt);  /* registry[LUA_RIDX_GLOBALS] = table of globals */  sethvalue(L, &mt, luaH_new(L));  luaH_setint(L, registry, LUA_RIDX_GLOBALS, &mt);}  /*** open parts of the state that may cause memory-allocation errors*/static void f_luaopen (lua_State *L, void *ud) {  global_State *g = G(L);  UNUSED(ud);  stack_init(L, L);  /* init stack */  init_registry(L, g);  luaS_resize(L, MINSTRTABSIZE);  /* initial size of string table */  luaT_init(L);  luaX_init(L);  /* pre-create memory-error message */  g->memerrmsg = luaS_newliteral(L, MEMERRMSG);  luaS_fix(g->memerrmsg);  /* it should never be collected */  g->gcrunning = 1;  /* allow gc */}  /*** preinitialize a state with consistent values without allocating** any memory (to avoid errors)*/static void preinit_state (lua_State *L, global_State *g) {  G(L) = g;  L->stack = NULL;  L->ci = NULL;  L->stacksize = 0;  L->errorJmp = NULL;  L->nCcalls = 0;  L->hook = NULL;  L->hookmask = 0;  L->basehookcount = 0;  L->allowhook = 1;  resethookcount(L);  L->openupval = NULL;  L->nny = 1;  L->status = LUA_OK;  L->errfunc = 0;}  static void close_state (lua_State *L) {  global_State *g = G(L);  luaF_close(L, L->stack);  /* close all upvalues for this thread */  luaC_freeallobjects(L);  /* collect all objects */  luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);  luaZ_freebuffer(L, &g->buff);  freestack(L);  lua_assert(gettotalbytes(g) == sizeof(LG));  (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0);  /* free main block */}  LUA_API lua_State *lua_newthread (lua_State *L) {  lua_State *L1;  lua_lock(L);  luaC_checkGC(L);  L1 = &luaC_newobj(L, LUA_TTHREAD, sizeof(LX), NULL, offsetof(LX, l))->th;  setthvalue(L, L->top, L1);  api_incr_top(L);  preinit_state(L1, G(L));  L1->hookmask = L->hookmask;  L1->basehookcount = L->basehookcount;  L1->hook = L->hook;  resethookcount(L1);  luai_userstatethread(L, L1);  stack_init(L1, L);  /* init stack */  lua_unlock(L);  return L1;}  void luaE_freethread (lua_State *L, lua_State *L1) {  LX *l = fromstate(L1);  luaF_close(L1, L1->stack);  /* close all upvalues for this thread */  lua_assert(L1->openupval == NULL);  luai_userstatefree(L, L1);  freestack(L1);  luaM_free(L, l);}  LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {  int i;  lua_State *L;  global_State *g;  LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));  if (l == NULL) return NULL;  L = &l->l.l;  g = &l->g;  L->next = NULL;  L->tt = LUA_TTHREAD;  g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);  L->marked = luaC_white(g);  g->gckind = KGC_NORMAL;  preinit_state(L, g);  g->frealloc = f;  g->ud = ud;  g->mainthread = L;  g->seed = makeseed(L);  g->uvhead.u.l.prev = &g->uvhead;  g->uvhead.u.l.next = &g->uvhead;  g->gcrunning = 0;  /* no GC while building state */  g->GCestimate = 0;  g->strt.size = 0;  g->strt.nuse = 0;  g->strt.hash = NULL;  setnilvalue(&g->l_registry);  luaZ_initbuffer(L, &g->buff);  g->panic = NULL;  g->version = lua_version(NULL);  g->gcstate = GCSpause;  g->allgc = NULL;  g->finobj = NULL;  g->tobefnz = NULL;  g->sweepgc = g->sweepfin = NULL;  g->gray = g->grayagain = NULL;  g->weak = g->ephemeron = g->allweak = NULL;  g->totalbytes = sizeof(LG);  g->GCdebt = 0;  g->gcpause = LUAI_GCPAUSE;  g->gcmajorinc = LUAI_GCMAJOR;  g->gcstepmul = LUAI_GCMUL;  for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;  if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {    /* memory allocation error: free partial state */    close_state(L);    L = NULL;  }  else    luai_userstateopen(L);  return L;}  LUA_API void lua_close (lua_State *L) {  L = G(L)->mainthread;  /* only the main thread can be closed */  lua_lock(L);  luai_userstateclose(L);  close_state(L);}