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/*

** $Id: lstate.c,v 2.92 2011/10/03 17:54:25 roberto Exp $

** Global State

** See Copyright Notice in lua.h

*/

#include 

#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"

/*

** 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)))

/*

** 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->uvhead.u.l.prev = &g->uvhead;

  g->uvhead.u.l.next = &g->uvhead;

  g->gcrunning = 0;  /* no GC while building state */

  g->lastmajormem = 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->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);

}