C++ setivalue函数代码示例

/*
** Main operation 'ra' = #rb'.
*/
void luaV_objlen (lua_State *L, StkId ra, const TValue *rb) {
  const TValue *tm;
  switch (ttype(rb)) {
    case LUA_TTABLE: {
      Table *h = hvalue(rb);
      tm = fasttm(L, h->metatable, TM_LEN);
      if (tm) break;  /* metamethod? break switch to call it */
      setivalue(ra, luaH_getn(h));  /* else primitive len */
      return;
    }
    case LUA_TSHRSTR: {
      setivalue(ra, tsvalue(rb)->shrlen);
      return;
    }
    case LUA_TLNGSTR: {
      setivalue(ra, tsvalue(rb)->u.lnglen);
      return;
    }
    default: {  /* try metamethod */
      tm = luaT_gettmbyobj(L, rb, TM_LEN);
      if (ttisnil(tm))  /* no metamethod? */
        luaG_typeerror(L, rb, "get length of");
      break;
    }
  }
  luaT_callTM(L, tm, rb, rb, ra, 1);
}

static void lll_forprep (lua_State *L, TValue *ra)
{
    TValue *init = ra;
    TValue *plimit = ra + 1;
    TValue *pstep = ra + 2;
    lua_Integer ilimit;
    int stopnow;
    if (ttisinteger(init) && ttisinteger(pstep) &&
        forlimit(plimit, &ilimit, ivalue(pstep), &stopnow)) {
      /* all values are integer */
      lua_Integer initv = (stopnow ? 0 : ivalue(init));
      setivalue(plimit, ilimit);
      setivalue(init, initv - ivalue(pstep));
    }
    else {  /* try making all values floats */
      lua_Number ninit; lua_Number nlimit; lua_Number nstep;
      if (!tonumber(plimit, &nlimit))
        luaG_runerror(L, "'for' limit must be a number");
      setfltvalue(plimit, nlimit);
      if (!tonumber(pstep, &nstep))
        luaG_runerror(L, "'for' step must be a number");
      setfltvalue(pstep, nstep);
      if (!tonumber(init, &ninit))
        luaG_runerror(L, "'for' initial value must be a number");
      setfltvalue(init, luai_numsub(L, ninit, nstep));
    }
}

void luaO_arith (lua_State *L, int op, const TValue *p1, const TValue *p2,
                 TValue *res) {
  switch (op) {
    case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR:
    case LUA_OPSHL: case LUA_OPSHR:
    case LUA_OPBNOT: {  /* operate only on integers */
      lua_Integer i1; lua_Integer i2;
      if (tointeger(p1, &i1) && tointeger(p2, &i2)) {
        setivalue(res, intarith(L, op, i1, i2));
        return;
      }
      else break;  /* go to the end */
    }
#ifndef _KERNEL
    case LUA_OPDIV: case LUA_OPPOW: {  /* operate only on floats */
      lua_Number n1; lua_Number n2;
      if (tonumber(p1, &n1) && tonumber(p2, &n2)) {
        setfltvalue(res, numarith(L, op, n1, n2));
        return;
      }
      else break;  /* go to the end */
    }
#endif
    default: {  /* other operations */
#ifndef _KERNEL
      lua_Number n1; lua_Number n2;
      if (ttisinteger(p1) && ttisinteger(p2)) {
        setivalue(res, intarith(L, op, ivalue(p1), ivalue(p2)));
        return;
      }
      else if (tonumber(p1, &n1) && tonumber(p2, &n2)) {
        setfltvalue(res, numarith(L, op, n1, n2));
        return;
      }
#else /* _KERNEL */
      lua_Integer i1; lua_Integer i2;
      if (tointeger(p1, &i1) && tointeger(p2, &i2)) {
        setivalue(res, intarith(L, op, i1, i2));
        return;
      }
#endif
      else break;  /* go to the end */
    }
  }
  /* could not perform raw operation; try metamethod */
  lua_assert(L != NULL);  /* should not fail when folding (compile time) */
  luaT_trybinTM(L, p1, p2, res, cast(TMS, (op - LUA_OPADD) + TM_ADD));
}

/*
** Add constant 'v' to prototype's list of constants (field 'k').
** Use scanner's table to cache position of constants in constant list
** and try to reuse constants. Because some values should not be used
** as keys (nil cannot be a key, integer keys can collapse with float
** keys), the caller must provide a useful 'key' for indexing the cache.
*/
static int addk (FuncState *fs, TValue *key, TValue *v) {
  lua_State *L = fs->ls->L;
  Proto *f = fs->f;
  TValue *idx = luaH_set(L, fs->ls->h, key);  /* index scanner table */
  int k, oldsize;
  if (ttisinteger(idx)) {  /* is there an index there? */
    k = cast_int(ivalue(idx));
    /* correct value? (warning: must distinguish floats from integers!) */
    if (k < fs->nk && ttype(&f->k[k]) == ttype(v) &&
                      luaV_rawequalobj(&f->k[k], v))
      return k;  /* reuse index */
  }
  /* constant not found; create a new entry */
  oldsize = f->sizek;
  k = fs->nk;
  /* numerical value does not need GC barrier;
     table has no metatable, so it does not need to invalidate cache */
  setivalue(idx, k);
  luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants");
  while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
  setobj(L, &f->k[k], v);
  fs->nk++;
  luaC_barrier(L, f, v);
  return k;
}

static void LoadConstants (LoadState *S, Proto *f) {
  int i;
  int n = LoadInt(S);
  f->k = luaM_newvector(S->L, n, TValue);
  f->sizek = n;
  for (i = 0; i < n; i++)
    setnilvalue(&f->k[i]);
  for (i = 0; i < n; i++) {
    TValue *o = &f->k[i];
    int t = LoadByte(S);
    switch (t) {
    case LUA_TNIL:
      setnilvalue(o);
      break;
    case LUA_TBOOLEAN:
      setbvalue(o, LoadByte(S));
      break;
    case LUA_TNUMFLT:
      setfltvalue(o, LoadNumber(S));
      break;
    case LUA_TNUMINT:
      setivalue(o, LoadInteger(S));
      break;
    case LUA_TSHRSTR:
    case LUA_TLNGSTR:
      setsvalue2n(S->L, o, LoadString(S));
      break;
    default:
      lua_assert(0);
    }
  }
}

LUA_API int lua_geti (lua_State *L, int idx, lua_Integer n) {
  StkId t;
  lua_lock(L);
  t = index2addr(L, idx);
  setivalue(L->top, n);
  api_incr_top(L);
  luaV_gettable(L, t, L->top - 1, L->top - 1);
  lua_unlock(L);
  return ttnov(L->top - 1);
}

LUA_API void lua_seti (lua_State *L, int idx, lua_Integer n) {
  StkId t;
  lua_lock(L);
  api_checknelems(L, 1);
  t = index2addr(L, idx);
  setivalue(L->top++, n);
  luaV_settable(L, t, L->top - 1, L->top - 2);
  L->top -= 2;  /* pop value and key */
  lua_unlock(L);
}

/*
** If expression is a numeric constant, fills 'v' with its value
** and returns 1. Otherwise, returns 0.
*/
static int tonumeral(expdesc *e, TValue *v) {
  if (hasjumps(e))
    return 0;  /* not a numeral */
  switch (e->k) {
    case VKINT:
      if (v) setivalue(v, e->u.ival);
      return 1;
    case VKFLT:
      if (v) setfltvalue(v, e->u.nval);
      return 1;
    default: return 0;
  }
}

static int tonumeral(expdesc *e, TValue *v) {
  if (e->t != NO_JUMP || e->f != NO_JUMP)
    return 0;  /* not a numeral */
  switch (e->k) {
    case VKINT:
      if (v) setivalue(v, e->u.ival);
      return 1;
#ifndef _KERNEL
    case VKFLT:
      if (v) setfltvalue(v, e->u.nval);
      return 1;
#endif
    default: return 0;
  }
}

int luaT_callorderiTM (lua_State *L, const TValue *p1, int v2,
                       int inv, int isfloat, TMS event) {
  TValue aux; const TValue *p2;
  if (isfloat) {
    setfltvalue(&aux, cast_num(v2));
  }
  else
    setivalue(&aux, v2);
  if (inv) {  /* arguments were exchanged? */
    p2 = p1; p1 = &aux;  /* correct them */
  }
  else
    p2 = &aux;
  return luaT_callorderTM(L, p1, p2, event);
}

LUA_API void lua_seti (lua_State *L, int idx, lua_Integer n) {
  StkId t;
  const TValue *slot;
  lua_lock(L);
  api_checknelems(L, 1);
  t = index2addr(L, idx);
  if (luaV_fastset(L, t, n, slot, luaH_getint, L->top - 1))
    L->top--;  /* pop value */
  else {
    setivalue(L->top, n);
    api_incr_top(L);
    luaV_finishset(L, t, L->top - 1, L->top - 2, slot);
    L->top -= 2;  /* pop value and key */
  }
  lua_unlock(L);
}

LUA_API int lua_geti (lua_State *L, int idx, lua_Integer n) {
  StkId t;
  const TValue *slot;
  lua_lock(L);
  t = index2addr(L, idx);
  if (luaV_fastget(L, t, n, slot, luaH_getint)) {
    setobj2s(L, L->top, slot);
    api_incr_top(L);
  }
  else {
    setivalue(L->top, n);
    api_incr_top(L);
    luaV_finishget(L, t, L->top - 1, L->top - 1, slot);
  }
  lua_unlock(L);
  return ttnov(L->top - 1);
}

int luaH_next (lua_State *L, Table *t, StkId key) {
    int i = findindex(L, t, key);  /* find original element */
    for (i++; i < t->sizearray; i++) {  /* try first array part */
        if (!ttisnil(&t->array[i])) {  /* a non-nil value? */
            setivalue(key, i+1);
            setobj2s(L, key+1, &t->array[i]);
            return 1;
        }
    }
    for (i -= t->sizearray; i < sizenode(t); i++) {  /* then hash part */
        if (!ttisnil(gval(gnode(t, i)))) {  /* a non-nil value? */
            setobj2s(L, key, key2tval(gnode(t, i)));
            setobj2s(L, key+1, gval(gnode(t, i)));
            return 1;
        }
    }
    return 0;  /* no more elements */
}

static int addk (FuncState *fs, TValue *k, TValue *v) {
  lua_State *L = fs->L;
  TValue *idx = luaH_set(L, fs->h, k);
#ifdef LUA_TINT
  /* Note: Integer-valued LUA_TNUMBER's are handled as in unpatched Lua (below)
  */
  if (ttype(idx)==LUA_TINT) {
    int i;
# ifdef LNUM_INT64
    lua_assert( (int)ivalue(idx) == ivalue(idx) );  /* make sure no data is lost in the casting */
# endif
    i= (int)ivalue(idx);
    lua_assert(luaO_rawequalObj(&fs->f->k[i], v));
    return i;
  }
  else if (ttype(idx)==LUA_TNUMBER) {
#else
  if (ttisnumber(idx)) {
#endif
    int i= cast_int(nvalue_fast(idx));
    lua_assert(luaO_rawequalObj(&fs->f->k[i], v));
    return i;
  }
  else {  /* constant not found; create a new entry */
    Proto *f = fs->f;
    int oldsize = f->sizek;
    setivalue(idx, fs->nk);
    luaM_growvector(L, f->k, fs->nk, f->sizek, TValue,
                    MAXARG_Bx, "constant table overflow");
    while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]);
    setobj(L, &f->k[fs->nk], v);
    luaC_barrier(L, f, v);
    return fs->nk++;
  }
}


int luaK_stringK (FuncState *fs, TString *s) {
  TValue o;
  setsvalue(fs->L, &o, s);
  return addk(fs, &o, &o);
}

/*
 * If 'obj' is a string, it is tried to be interpreted as a number.
 */
const TValue *luaV_tonumber ( const TValue *obj, TValue *n) {
  lua_Number d;
  lua_Integer i;
  
  if (ttisnumber(obj)) return obj;

  if (ttisstring(obj)) {
    switch( luaO_str2d( svalue(obj), &d, &i ) ) {
        case TK_INT:
            setivalue(n,i); return n;
        case TK_NUMBER: 
            setnvalue(n,d); return n;
#ifdef LNUM_COMPLEX
        case TK_NUMBER2:    /* "N.NNNi", != 0 */
            setnvalue_complex_fast(n, d*I); return n;
#endif
        }
    }
  return NULL;
}