/*
** $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 */
}