/*

** $Id: lfunc.c,v 2.12.1.2 2007/12/28 14:58:43 roberto Exp $

** Auxiliary functions to manipulate prototypes and closures

** See Copyright Notice in lua.h

*/

#include <stddef.h>

#define lfunc_c

#define LUA_CORE

#include "lua.h"

#include "lfunc.h"

#include "lgc.h"

#include "lmem.h"

#include "lobject.h"

#include "lstate.h"

Closure *luaF_newCclosure (lua_State *L, int nelems, Table *e) {

  Closure *c = cast(Closure *, luaM_malloc(L, sizeCclosure(nelems)));

  luaC_link(L, obj2gco(c), LUA_TFUNCTION);

  c->c.isC = 1;

  c->c.env = e;

  c->c.nupvalues = cast_byte(nelems);

  return c;

}

Closure *luaF_newLclosure (lua_State *L, int nelems, Table *e) {

  Closure *c = cast(Closure *, luaM_malloc(L, sizeLclosure(nelems)));

  luaC_link(L, obj2gco(c), LUA_TFUNCTION);

  c->l.isC = 0;

  c->l.env = e;

  c->l.nupvalues = cast_byte(nelems);

  while (nelems--) c->l.upvals[nelems] = NULL;

  return c;

}

UpVal *luaF_newupval (lua_State *L) {

  UpVal *uv = luaM_new(L, UpVal);

  luaC_link(L, obj2gco(uv), LUA_TUPVAL);

  uv->v = &uv->u.value;

  setnilvalue(uv->v);

  return uv;

}

UpVal *luaF_findupval (lua_State *L, StkId level) {

  global_State *g = G(L);

  GCObject **pp = &L->openupval;

  UpVal *p;

  UpVal *uv;

  while (*pp != NULL && (p = ngcotouv(*pp))->v >= level) {

    lua_assert(p->v != &p->u.value);

    if (p->v == level) {  /* found a corresponding upvalue? */

      if (isdead(g, obj2gco(p)))  /* is it dead? */

        changewhite(obj2gco(p));  /* ressurect it */

      return p;

    }

    pp = &p->next;

  }

  uv = luaM_new(L, UpVal);  /* not found: create a new one */

  uv->tt = LUA_TUPVAL;

  uv->marked = luaC_white(g);

  uv->v = level;  /* current value lives in the stack */

  uv->next = *pp;  /* chain it in the proper position */

  *pp = obj2gco(uv);

  uv->u.l.prev = &g->uvhead;  /* double link it in `uvhead' list */

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

  uv->u.l.next->u.l.prev = uv;

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

  lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);

  return uv;

}

static void unlinkupval (UpVal *uv) {

  lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);

  uv->u.l.next->u.l.prev = uv->u.l.prev;  /* remove from `uvhead' list */

  uv->u.l.prev->u.l.next = uv->u.l.next;

}

void luaF_freeupval (lua_State *L, UpVal *uv) {

  if (uv->v != &uv->u.value)  /* is it open? */

    unlinkupval(uv);  /* remove from open list */

  luaM_free(L, uv);  /* free upvalue */

}

void luaF_close (lua_State *L, StkId level) {

  UpVal *uv;

  global_State *g = G(L);

  while (L->openupval != NULL && (uv = ngcotouv(L->openupval))->v >= level) {

    GCObject *o = obj2gco(uv);

    lua_assert(!isblack(o) && uv->v != &uv->u.value);

    L->openupval = uv->next;  /* remove from `open' list */

    if (isdead(g, o))

      luaF_freeupval(L, uv);  /* free upvalue */

    else {

      unlinkupval(uv);

      setobj(L, &uv->u.value, uv->v);

      uv->v = &uv->u.value;  /* now current value lives here */

      luaC_linkupval(L, uv);  /* link upvalue into `gcroot' list */

    }

  }

}

Proto *luaF_newproto (lua_State *L) {

  Proto *f = luaM_new(L, Proto);

  luaC_link(L, obj2gco(f), LUA_TPROTO);

  f->k = NULL;

  f->sizek = 0;

  f->p = NULL;

  f->sizep = 0;

  f->code = NULL;

  f->sizecode = 0;

  f->sizelineinfo = 0;

  f->sizeupvalues = 0;

  f->nups = 0;

  f->upvalues = NULL;

  f->numparams = 0;

  f->is_vararg = 0;

  f->maxstacksize = 0;

  f->lineinfo = NULL;

  f->sizelocvars = 0;

  f->locvars = NULL;

  f->linedefined = 0;

  f->lastlinedefined = 0;

  f->source = NULL;

  return f;

}

void luaF_freeproto (lua_State *L, Proto *f) {

  luaM_freearray(L, f->code, f->sizecode, Instruction);

  luaM_freearray(L, f->p, f->sizep, Proto *);

  luaM_freearray(L, f->k, f->sizek, TValue);

  luaM_freearray(L, f->lineinfo, f->sizelineinfo, int);

  luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);

  luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);

  luaM_free(L, f);

}

void luaF_freeclosure (lua_State *L, Closure *c) {

  int size = (c->c.isC) ? sizeCclosure(c->c.nupvalues) :

                          sizeLclosure(c->l.nupvalues);

  luaM_freemem(L, c, size);

}

/*

** Look for n-th local variable at line `line' in function `func'.

** Returns NULL if not found.

*/

const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {

  int i;

  for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {

    if (pc < f->locvars[i].endpc) {  /* is variable active? */

      local_number--;

      if (local_number == 0)

        return getstr(f->locvars[i].varname);

    }

  }

  return NULL;  /* not found */

}