Mesen-SX/Lua/lapi.c

/*
** $Id: lapi.c,v 2.259 2016/02/29 14:27:14 roberto Exp $
** Lua API
** See Copyright Notice in lua.h
*/

#define lapi_c
#define LUA_CORE

#include "lprefix.h"


#include <stdarg.h>
#include <string.h>

#include "lua.h"

#include "lapi.h"
#include "ldebug.h"
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "lundump.h"
#include "lvm.h"


const char lua_ident[] =
	"$LuaVersion: " LUA_COPYRIGHT " $"
	"$LuaAuthors: " LUA_AUTHORS " $";


/* value at a non-valid index */
#define NONVALIDVALUE		cast(TValue *, luaO_nilobject)

/* corresponding test */
#define isvalid(o)	((o) != luaO_nilobject)

/* test for pseudo index */
#define ispseudo(i)		((i) <= LUA_REGISTRYINDEX)

/* test for upvalue */
#define isupvalue(i)		((i) < LUA_REGISTRYINDEX)

/* test for valid but not pseudo index */
#define isstackindex(i, o)	(isvalid(o) && !ispseudo(i))

#define api_checkvalidindex(l,o)  api_check(l, isvalid(o), "invalid index")

#define api_checkstackindex(l, i, o)  \
	api_check(l, isstackindex(i, o), "index not in the stack")


static TValue* index2addr(lua_State* L, int idx)
{
	CallInfo* ci = L->ci;
	if (idx > 0)
	{
		TValue* o = ci->func + idx;
		api_check(L, idx <= ci->top - (ci->func + 1), "unacceptable index");
		if (o >= L->top) return NONVALIDVALUE;
		else return o;
	}
	else if (!ispseudo(idx))
	{
		/* negative index */
		api_check(L, idx != 0 && -idx <= L->top - (ci->func + 1), "invalid index");
		return L->top + idx;
	}
	else if (idx == LUA_REGISTRYINDEX)
		return &G(L)->l_registry;
	else
	{
		/* upvalues */
		idx = LUA_REGISTRYINDEX - idx;
		api_check(L, idx <= MAXUPVAL + 1, "upvalue index too large");
		if (ttislcf(ci->func)) /* light C function? */
			return NONVALIDVALUE; /* it has no upvalues */
		else
		{
			CClosure* func = clCvalue(ci->func);
			return (idx <= func->nupvalues) ? &func->upvalue[idx - 1] : NONVALIDVALUE;
		}
	}
}


/*
** to be called by 'lua_checkstack' in protected mode, to grow stack
** capturing memory errors
*/
static void growstack(lua_State* L, void* ud)
{
	int size = *(int*)ud;
	luaD_growstack(L, size);
}


LUA_API int lua_checkstack(lua_State* L, int n)
{
	int res;
	CallInfo* ci = L->ci;
	lua_lock(L);
	api_check(L, n >= 0, "negative 'n'");
	if (L->stack_last - L->top > n) /* stack large enough? */
		res = 1; /* yes; check is OK */
	else
	{
		/* no; need to grow stack */
		int inuse = cast_int(L->top - L->stack) + EXTRA_STACK;
		if (inuse > LUAI_MAXSTACK - n) /* can grow without overflow? */
			res = 0; /* no */
		else /* try to grow stack */
			res = (luaD_rawrunprotected(L, &growstack, &n) == LUA_OK);
	}
	if (res && ci->top < L->top + n)
		ci->top = L->top + n; /* adjust frame top */
	lua_unlock(L);
	return res;
}


LUA_API void lua_xmove(lua_State* from, lua_State* to, int n)
{
	int i;
	if (from == to) return;
	lua_lock(to);
	api_checknelems(from, n);
	api_check(from, G(from) == G(to), "moving among independent states");
	api_check(from, to->ci->top - to->top >= n, "stack overflow");
	from->top -= n;
	for (i = 0; i < n; i++)
	{
		setobj2s(to, to->top, from->top + i);
		to->top++; /* stack already checked by previous 'api_check' */
	}
	lua_unlock(to);
}


LUA_API lua_CFunction lua_atpanic(lua_State* L, lua_CFunction panicf)
{
	lua_CFunction old;
	lua_lock(L);
	old = G(L)->panic;
	G(L)->panic = panicf;
	lua_unlock(L);
	return old;
}


LUA_API const lua_Number* lua_version(lua_State* L)
{
	static const lua_Number version = LUA_VERSION_NUM;
	if (L == NULL) return &version;
	else return G(L)->version;
}


/*
** basic stack manipulation
*/


/*
** convert an acceptable stack index into an absolute index
*/
LUA_API int lua_absindex(lua_State* L, int idx)
{
	return (idx > 0 || ispseudo(idx))
		       ? idx
		       : cast_int(L->top - L->ci->func) + idx;
}


LUA_API int lua_gettop(lua_State* L)
{
	return cast_int(L->top - (L->ci->func + 1));
}


LUA_API void lua_settop(lua_State* L, int idx)
{
	StkId func = L->ci->func;
	lua_lock(L);
	if (idx >= 0)
	{
		api_check(L, idx <= L->stack_last - (func + 1), "new top too large");
		while (L->top < (func + 1) + idx)
			setnilvalue(L->top++);
		L->top = (func + 1) + idx;
	}
	else
	{
		api_check(L, -(idx+1) <= (L->top - (func + 1)), "invalid new top");
		L->top += idx + 1; /* 'subtract' index (index is negative) */
	}
	lua_unlock(L);
}


/*
** Reverse the stack segment from 'from' to 'to'
** (auxiliary to 'lua_rotate')
*/
static void reverse(lua_State* L, StkId from, StkId to)
{
	for (; from < to; from++, to--)
	{
		TValue temp;
		setobj(L, &temp, from);
		setobjs2s(L, from, to);
		setobj2s(L, to, &temp);
	}
}


/*
** Let x = AB, where A is a prefix of length 'n'. Then,
** rotate x n == BA. But BA == (A^r . B^r)^r.
*/
LUA_API void lua_rotate(lua_State* L, int idx, int n)
{
	StkId p, t, m;
	lua_lock(L);
	t = L->top - 1; /* end of stack segment being rotated */
	p = index2addr(L, idx); /* start of segment */
	api_checkstackindex(L, idx, p);
	api_check(L, (n >= 0 ? n : -n) <= (t - p + 1), "invalid 'n'");
	m = (n >= 0 ? t - n : p - n - 1); /* end of prefix */
	reverse(L, p, m); /* reverse the prefix with length 'n' */
	reverse(L, m + 1, t); /* reverse the suffix */
	reverse(L, p, t); /* reverse the entire segment */
	lua_unlock(L);
}


LUA_API void lua_copy(lua_State* L, int fromidx, int toidx)
{
	TValue *fr, *to;
	lua_lock(L);
	fr = index2addr(L, fromidx);
	to = index2addr(L, toidx);
	api_checkvalidindex(L, to);
	setobj(L, to, fr);
	if (isupvalue(toidx)) /* function upvalue? */
		luaC_barrier(L, clCvalue(L->ci->func), fr);
	/* LUA_REGISTRYINDEX does not need gc barrier
	   (collector revisits it before finishing collection) */
	lua_unlock(L);
}


LUA_API void lua_pushvalue(lua_State* L, int idx)
{
	lua_lock(L);
	setobj2s(L, L->top, index2addr(L, idx));
	api_incr_top(L);
	lua_unlock(L);
}


/*
** access functions (stack -> C)
*/


LUA_API int lua_type(lua_State* L, int idx)
{
	StkId o = index2addr(L, idx);
	return (isvalid(o) ? ttnov(o) : LUA_TNONE);
}


LUA_API const char* lua_typename(lua_State* L, int t)
{
	UNUSED(L);
	api_check(L, LUA_TNONE <= t && t < LUA_NUMTAGS, "invalid tag");
	return ttypename(t);
}


LUA_API int lua_iscfunction(lua_State* L, int idx)
{
	StkId o = index2addr(L, idx);
	return (ttislcf(o) || (ttisCclosure(o)));
}


LUA_API int lua_isinteger(lua_State* L, int idx)
{
	StkId o = index2addr(L, idx);
	return ttisinteger(o);
}


LUA_API int lua_isnumber(lua_State* L, int idx)
{
	lua_Number n;
	const TValue* o = index2addr(L, idx);
	return tonumber(o, &n);
}


LUA_API int lua_isstring(lua_State* L, int idx)
{
	const TValue* o = index2addr(L, idx);
	return (ttisstring(o) || cvt2str(o));
}


LUA_API int lua_isuserdata(lua_State* L, int idx)
{
	const TValue* o = index2addr(L, idx);
	return (ttisfulluserdata(o) || ttislightuserdata(o));
}


LUA_API int lua_rawequal(lua_State* L, int index1, int index2)
{
	StkId o1 = index2addr(L, index1);
	StkId o2 = index2addr(L, index2);
	return (isvalid(o1) && isvalid(o2)) ? luaV_rawequalobj(o1, o2) : 0;
}


LUA_API void lua_arith(lua_State* L, int op)
{
	lua_lock(L);
	if (op != LUA_OPUNM && op != LUA_OPBNOT)
		api_checknelems(L, 2); /* all other operations expect two operands */
	else
	{
		/* for unary operations, add fake 2nd operand */
		api_checknelems(L, 1);
		setobjs2s(L, L->top, L->top - 1);
		api_incr_top(L);
	}
	/* first operand at top - 2, second at top - 1; result go to top - 2 */
	luaO_arith(L, op, L->top - 2, L->top - 1, L->top - 2);
	L->top--; /* remove second operand */
	lua_unlock(L);
}


LUA_API int lua_compare(lua_State* L, int index1, int index2, int op)
{
	StkId o1, o2;
	int i = 0;
	lua_lock(L); /* may call tag method */
	o1 = index2addr(L, index1);
	o2 = index2addr(L, index2);
	if (isvalid(o1) && isvalid(o2))
	{
		switch (op)
		{
		case LUA_OPEQ: i = luaV_equalobj(L, o1, o2);
			break;
		case LUA_OPLT: i = luaV_lessthan(L, o1, o2);
			break;
		case LUA_OPLE: i = luaV_lessequal(L, o1, o2);
			break;
		default: api_check(L, 0, "invalid option");
		}
	}
	lua_unlock(L);
	return i;
}


LUA_API size_t lua_stringtonumber(lua_State* L, const char* s)
{
	size_t sz = luaO_str2num(s, L->top);
	if (sz != 0)
	api_incr_top(L);
	return sz;
}


LUA_API lua_Number lua_tonumberx(lua_State* L, int idx, int* pisnum)
{
	lua_Number n;
	const TValue* o = index2addr(L, idx);
	int isnum = tonumber(o, &n);
	if (!isnum)
		n = 0; /* call to 'tonumber' may change 'n' even if it fails */
	if (pisnum) *pisnum = isnum;
	return n;
}


LUA_API lua_Integer lua_tointegerx(lua_State* L, int idx, int* pisnum)
{
	lua_Integer res;
	const TValue* o = index2addr(L, idx);
	int isnum = tointeger(o, &res);
	if (!isnum)
		res = 0; /* call to 'tointeger' may change 'n' even if it fails */
	if (pisnum) *pisnum = isnum;
	return res;
}


LUA_API int lua_toboolean(lua_State* L, int idx)
{
	const TValue* o = index2addr(L, idx);
	return !l_isfalse(o);
}


LUA_API const char* lua_tolstring(lua_State* L, int idx, size_t* len)
{
	StkId o = index2addr(L, idx);
	if (!ttisstring(o))
	{
		if (!cvt2str(o))
		{
			/* not convertible? */
			if (len != NULL) *len = 0;
			return NULL;
		}
		lua_lock(L); /* 'luaO_tostring' may create a new string */
		luaO_tostring(L, o);
		luaC_checkGC(L);
		o = index2addr(L, idx); /* previous call may reallocate the stack */
		lua_unlock(L);
	}
	if (len != NULL)
		*len = vslen(o);
	return svalue(o);
}


LUA_API size_t lua_rawlen(lua_State* L, int idx)
{
	StkId o = index2addr(L, idx);
	switch (ttype(o))
	{
	case LUA_TSHRSTR: return tsvalue(o)->shrlen;
	case LUA_TLNGSTR: return tsvalue(o)->u.lnglen;
	case LUA_TUSERDATA: return uvalue(o)->len;
	case LUA_TTABLE: return luaH_getn(hvalue(o));
	default: return 0;
	}
}


LUA_API lua_CFunction lua_tocfunction(lua_State* L, int idx)
{
	StkId o = index2addr(L, idx);
	if (ttislcf(o)) return fvalue(o);
	else if (ttisCclosure(o))
		return clCvalue(o)->f;
	else return NULL; /* not a C function */
}


LUA_API void* lua_touserdata(lua_State* L, int idx)
{
	StkId o = index2addr(L, idx);
	switch (ttnov(o))
	{
	case LUA_TUSERDATA: return getudatamem(uvalue(o));
	case LUA_TLIGHTUSERDATA: return pvalue(o);
	default: return NULL;
	}
}


LUA_API lua_State* lua_tothread(lua_State* L, int idx)
{
	StkId o = index2addr(L, idx);
	return (!ttisthread(o)) ? NULL : thvalue(o);
}


LUA_API const void* lua_topointer(lua_State* L, int idx)
{
	StkId o = index2addr(L, idx);
	switch (ttype(o))
	{
	case LUA_TTABLE: return hvalue(o);
	case LUA_TLCL: return clLvalue(o);
	case LUA_TCCL: return clCvalue(o);
	case LUA_TLCF: return cast(void *, cast(size_t, fvalue(o)));
	case LUA_TTHREAD: return thvalue(o);
	case LUA_TUSERDATA: return getudatamem(uvalue(o));
	case LUA_TLIGHTUSERDATA: return pvalue(o);
	default: return NULL;
	}
}


/*
** push functions (C -> stack)
*/


LUA_API void lua_pushnil(lua_State* L)
{
	lua_lock(L);
	setnilvalue(L->top);
	api_incr_top(L);
	lua_unlock(L);
}


LUA_API void lua_pushnumber(lua_State* L, lua_Number n)
{
	lua_lock(L);
	setfltvalue(L->top, n);
	api_incr_top(L);
	lua_unlock(L);
}


LUA_API void lua_pushinteger(lua_State* L, lua_Integer n)
{
	lua_lock(L);
	setivalue(L->top, n);
	api_incr_top(L);
	lua_unlock(L);
}


/*
** Pushes on the stack a string with given length. Avoid using 's' when
** 'len' == 0 (as 's' can be NULL in that case), due to later use of
** 'memcmp' and 'memcpy'.
*/
LUA_API const char* lua_pushlstring(lua_State* L, const char* s, size_t len)
{
	TString* ts;
	lua_lock(L);
	ts = (len == 0) ? luaS_new(L, "") : luaS_newlstr(L, s, len);
	setsvalue2s(L, L->top, ts);
	api_incr_top(L);
	luaC_checkGC(L);
	lua_unlock(L);
	return getstr(ts);
}


LUA_API const char* lua_pushstring(lua_State* L, const char* s)
{
	lua_lock(L);
	if (s == NULL)
		setnilvalue(L->top);
	else
	{
		TString* ts;
		ts = luaS_new(L, s);
		setsvalue2s(L, L->top, ts);
		s = getstr(ts); /* internal copy's address */
	}
	api_incr_top(L);
	luaC_checkGC(L);
	lua_unlock(L);
	return s;
}


LUA_API const char* lua_pushvfstring(lua_State* L, const char* fmt,
                                     va_list argp)
{
	const char* ret;
	lua_lock(L);
	ret = luaO_pushvfstring(L, fmt, argp);
	luaC_checkGC(L);
	lua_unlock(L);
	return ret;
}


LUA_API const char* lua_pushfstring(lua_State* L, const char* fmt, ...)
{
	const char* ret;
	va_list argp;
	lua_lock(L);
	va_start(argp, fmt);
	ret = luaO_pushvfstring(L, fmt, argp);
	va_end(argp);
	luaC_checkGC(L);
	lua_unlock(L);
	return ret;
}


LUA_API void lua_pushcclosure(lua_State* L, lua_CFunction fn, int n)
{
	lua_lock(L);
	if (n == 0)
	{
		setfvalue(L->top, fn);
	}
	else
	{
		CClosure* cl;
		api_checknelems(L, n);
		api_check(L, n <= MAXUPVAL, "upvalue index too large");
		cl = luaF_newCclosure(L, n);
		cl->f = fn;
		L->top -= n;
		while (n--)
		{
			setobj2n(L, &cl->upvalue[n], L->top + n);
			/* does not need barrier because closure is white */
		}
		setclCvalue(L, L->top, cl);
	}
	api_incr_top(L);
	luaC_checkGC(L);
	lua_unlock(L);
}


LUA_API void lua_pushboolean(lua_State* L, int b)
{
	lua_lock(L);
	setbvalue(L->top, (b != 0)); /* ensure that true is 1 */
	api_incr_top(L);
	lua_unlock(L);
}


LUA_API void lua_pushlightuserdata(lua_State* L, void* p)
{
	lua_lock(L);
	setpvalue(L->top, p);
	api_incr_top(L);
	lua_unlock(L);
}


LUA_API int lua_pushthread(lua_State* L)
{
	lua_lock(L);
	setthvalue(L, L->top, L);
	api_incr_top(L);
	lua_unlock(L);
	return (G(L)->mainthread == L);
}


/*
** get functions (Lua -> stack)
*/


static int auxgetstr(lua_State* L, const TValue* t, const char* k)
{
	const TValue* slot;
	TString* str = luaS_new(L, k);
	if (luaV_fastget(L, t, str, slot, luaH_getstr))
	{
		setobj2s(L, L->top, slot);
		api_incr_top(L);
	}
	else
	{
		setsvalue2s(L, L->top, str);
		api_incr_top(L);
		luaV_finishget(L, t, L->top - 1, L->top - 1, slot);
	}
	lua_unlock(L);
	return ttnov(L->top - 1);
}


LUA_API int lua_getglobal(lua_State* L, const char* name)
{
	Table* reg = hvalue(&G(L)->l_registry);
	lua_lock(L);
	return auxgetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
}


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


LUA_API int lua_getfield(lua_State* L, int idx, const char* k)
{
	lua_lock(L);
	return auxgetstr(L, index2addr(L, idx), k);
}


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);
}


LUA_API int lua_rawget(lua_State* L, int idx)
{
	StkId t;
	lua_lock(L);
	t = index2addr(L, idx);
	api_check(L, ttistable(t), "table expected");
	setobj2s(L, L->top - 1, luaH_get(hvalue(t), L->top - 1));
	lua_unlock(L);
	return ttnov(L->top - 1);
}


LUA_API int lua_rawgeti(lua_State* L, int idx, lua_Integer n)
{
	StkId t;
	lua_lock(L);
	t = index2addr(L, idx);
	api_check(L, ttistable(t), "table expected");
	setobj2s(L, L->top, luaH_getint(hvalue(t), n));
	api_incr_top(L);
	lua_unlock(L);
	return ttnov(L->top - 1);
}


LUA_API int lua_rawgetp(lua_State* L, int idx, const void* p)
{
	StkId t;
	TValue k;
	lua_lock(L);
	t = index2addr(L, idx);
	api_check(L, ttistable(t), "table expected");
	setpvalue(&k, cast(void *, p));
	setobj2s(L, L->top, luaH_get(hvalue(t), &k));
	api_incr_top(L);
	lua_unlock(L);
	return ttnov(L->top - 1);
}


LUA_API void lua_createtable(lua_State* L, int narray, int nrec)
{
	Table* t;
	lua_lock(L);
	t = luaH_new(L);
	sethvalue(L, L->top, t);
	api_incr_top(L);
	if (narray > 0 || nrec > 0)
		luaH_resize(L, t, narray, nrec);
	luaC_checkGC(L);
	lua_unlock(L);
}


LUA_API int lua_getmetatable(lua_State* L, int objindex)
{
	const TValue* obj;
	Table* mt;
	int res = 0;
	lua_lock(L);
	obj = index2addr(L, objindex);
	switch (ttnov(obj))
	{
	case LUA_TTABLE:
		mt = hvalue(obj)->metatable;
		break;
	case LUA_TUSERDATA:
		mt = uvalue(obj)->metatable;
		break;
	default:
		mt = G(L)->mt[ttnov(obj)];
		break;
	}
	if (mt != NULL)
	{
		sethvalue(L, L->top, mt);
		api_incr_top(L);
		res = 1;
	}
	lua_unlock(L);
	return res;
}


LUA_API int lua_getuservalue(lua_State* L, int idx)
{
	StkId o;
	lua_lock(L);
	o = index2addr(L, idx);
	api_check(L, ttisfulluserdata(o), "full userdata expected");
	getuservalue(L, uvalue(o), L->top);
	api_incr_top(L);
	lua_unlock(L);
	return ttnov(L->top - 1);
}


/*
** set functions (stack -> Lua)
*/

/*
** t[k] = value at the top of the stack (where 'k' is a string)
*/
static void auxsetstr(lua_State* L, const TValue* t, const char* k)
{
	const TValue* slot;
	TString* str = luaS_new(L, k);
	api_checknelems(L, 1);
	if (luaV_fastset(L, t, str, slot, luaH_getstr, L->top - 1))
		L->top--; /* pop value */
	else
	{
		setsvalue2s(L, L->top, str); /* push 'str' (to make it a TValue) */
		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); /* lock done by caller */
}


LUA_API void lua_setglobal(lua_State* L, const char* name)
{
	Table* reg = hvalue(&G(L)->l_registry);
	lua_lock(L); /* unlock done in 'auxsetstr' */
	auxsetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
}


LUA_API void lua_settable(lua_State* L, int idx)
{
	StkId t;
	lua_lock(L);
	api_checknelems(L, 2);
	t = index2addr(L, idx);
	luaV_settable(L, t, L->top - 2, L->top - 1);
	L->top -= 2; /* pop index and value */
	lua_unlock(L);
}


LUA_API void lua_setfield(lua_State* L, int idx, const char* k)
{
	lua_lock(L); /* unlock done in 'auxsetstr' */
	auxsetstr(L, index2addr(L, idx), k);
}


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 void lua_rawset(lua_State* L, int idx)
{
	StkId o;
	TValue* slot;
	lua_lock(L);
	api_checknelems(L, 2);
	o = index2addr(L, idx);
	api_check(L, ttistable(o), "table expected");
	slot = luaH_set(L, hvalue(o), L->top - 2);
	setobj2t(L, slot, L->top - 1);
	invalidateTMcache(hvalue(o));
	luaC_barrierback(L, hvalue(o), L->top-1);
	L->top -= 2;
	lua_unlock(L);
}


LUA_API void lua_rawseti(lua_State* L, int idx, lua_Integer n)
{
	StkId o;
	lua_lock(L);
	api_checknelems(L, 1);
	o = index2addr(L, idx);
	api_check(L, ttistable(o), "table expected");
	luaH_setint(L, hvalue(o), n, L->top - 1);
	luaC_barrierback(L, hvalue(o), L->top-1);
	L->top--;
	lua_unlock(L);
}


LUA_API void lua_rawsetp(lua_State* L, int idx, const void* p)
{
	StkId o;
	TValue k, *slot;
	lua_lock(L);
	api_checknelems(L, 1);
	o = index2addr(L, idx);
	api_check(L, ttistable(o), "table expected");
	setpvalue(&k, cast(void *, p));
	slot = luaH_set(L, hvalue(o), &k);
	setobj2t(L, slot, L->top - 1);
	luaC_barrierback(L, hvalue(o), L->top - 1);
	L->top--;
	lua_unlock(L);
}


LUA_API int lua_setmetatable(lua_State* L, int objindex)
{
	TValue* obj;
	Table* mt;
	lua_lock(L);
	api_checknelems(L, 1);
	obj = index2addr(L, objindex);
	if (ttisnil(L->top - 1))
		mt = NULL;
	else
	{
		api_check(L, ttistable(L->top - 1), "table expected");
		mt = hvalue(L->top - 1);
	}
	switch (ttnov(obj))
	{
	case LUA_TTABLE:
		{
			hvalue(obj)->metatable = mt;
			if (mt)
			{
				luaC_objbarrier(L, gcvalue(obj), mt);
				luaC_checkfinalizer(L, gcvalue(obj), mt);
			}
			break;
		}
	case LUA_TUSERDATA:
		{
			uvalue(obj)->metatable = mt;
			if (mt)
			{
				luaC_objbarrier(L, uvalue(obj), mt);
				luaC_checkfinalizer(L, gcvalue(obj), mt);
			}
			break;
		}
	default:
		{
			G(L)->mt[ttnov(obj)] = mt;
			break;
		}
	}
	L->top--;
	lua_unlock(L);
	return 1;
}


LUA_API void lua_setuservalue(lua_State* L, int idx)
{
	StkId o;
	lua_lock(L);
	api_checknelems(L, 1);
	o = index2addr(L, idx);
	api_check(L, ttisfulluserdata(o), "full userdata expected");
	setuservalue(L, uvalue(o), L->top - 1);
	luaC_barrier(L, gcvalue(o), L->top - 1);
	L->top--;
	lua_unlock(L);
}


/*
** 'load' and 'call' functions (run Lua code)
*/


#define checkresults(L,na,nr) \
     api_check(L, (nr) == LUA_MULTRET || (L->ci->top - L->top >= (nr) - (na)), \
	"results from function overflow current stack size")


LUA_API void lua_callk(lua_State* L, int nargs, int nresults,
                       lua_KContext ctx, lua_KFunction k)
{
	StkId func;
	lua_lock(L);
	api_check(L, k == NULL || !isLua(L->ci),
	          "cannot use continuations inside hooks");
	api_checknelems(L, nargs+1);
	api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
	checkresults(L, nargs, nresults);
	func = L->top - (nargs + 1);
	if (k != NULL && L->nny == 0)
	{
		/* need to prepare continuation? */
		L->ci->u.c.k = k; /* save continuation */
		L->ci->u.c.ctx = ctx; /* save context */
		luaD_call(L, func, nresults); /* do the call */
	}
	else /* no continuation or no yieldable */
		luaD_callnoyield(L, func, nresults); /* just do the call */
	adjustresults(L, nresults);
	lua_unlock(L);
}


/*
** Execute a protected call.
*/
struct CallS
{
	/* data to 'f_call' */
	StkId func;
	int nresults;
};


static void f_call(lua_State* L, void* ud)
{
	struct CallS* c = cast(struct CallS *, ud);
	luaD_callnoyield(L, c->func, c->nresults);
}


LUA_API int lua_pcallk(lua_State* L, int nargs, int nresults, int errfunc,
                       lua_KContext ctx, lua_KFunction k)
{
	struct CallS c;
	int status;
	ptrdiff_t func;
	lua_lock(L);
	api_check(L, k == NULL || !isLua(L->ci),
	          "cannot use continuations inside hooks");
	api_checknelems(L, nargs+1);
	api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
	checkresults(L, nargs, nresults);
	if (errfunc == 0)
		func = 0;
	else
	{
		StkId o = index2addr(L, errfunc);
		api_checkstackindex(L, errfunc, o);
		func = savestack(L, o);
	}
	c.func = L->top - (nargs + 1); /* function to be called */
	if (k == NULL || L->nny > 0)
	{
		/* no continuation or no yieldable? */
		c.nresults = nresults; /* do a 'conventional' protected call */
		status = luaD_pcall(L, f_call, &c, savestack(L, c.func), func);
	}
	else
	{
		/* prepare continuation (call is already protected by 'resume') */
		CallInfo* ci = L->ci;
		ci->u.c.k = k; /* save continuation */
		ci->u.c.ctx = ctx; /* save context */
		/* save information for error recovery */
		ci->extra = savestack(L, c.func);
		ci->u.c.old_errfunc = L->errfunc;
		L->errfunc = func;
		setoah(ci->callstatus, L->allowhook); /* save value of 'allowhook' */
		ci->callstatus |= CIST_YPCALL; /* function can do error recovery */
		luaD_call(L, c.func, nresults); /* do the call */
		ci->callstatus &= ~CIST_YPCALL;
		L->errfunc = ci->u.c.old_errfunc;
		status = LUA_OK; /* if it is here, there were no errors */
	}
	adjustresults(L, nresults);
	lua_unlock(L);
	return status;
}


LUA_API int lua_load(lua_State* L, lua_Reader reader, void* data,
                     const char* chunkname, const char* mode)
{
	ZIO z;
	int status;
	lua_lock(L);
	if (!chunkname) chunkname = "?";
	luaZ_init(L, &z, reader, data);
	status = luaD_protectedparser(L, &z, chunkname, mode);
	if (status == LUA_OK)
	{
		/* no errors? */
		LClosure* f = clLvalue(L->top - 1); /* get newly created function */
		if (f->nupvalues >= 1)
		{
			/* does it have an upvalue? */
			/* get global table from registry */
			Table* reg = hvalue(&G(L)->l_registry);
			const TValue* gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
			/* set global table as 1st upvalue of 'f' (may be LUA_ENV) */
			setobj(L, f->upvals[0]->v, gt);
			luaC_upvalbarrier(L, f->upvals[0]);
		}
	}
	lua_unlock(L);
	return status;
}


LUA_API int lua_dump(lua_State* L, lua_Writer writer, void* data, int strip)
{
	int status;
	TValue* o;
	lua_lock(L);
	api_checknelems(L, 1);
	o = L->top - 1;
	if (isLfunction(o))
		status = luaU_dump(L, getproto(o), writer, data, strip);
	else
		status = 1;
	lua_unlock(L);
	return status;
}


LUA_API int lua_status(lua_State* L)
{
	return L->status;
}


/*
** Garbage-collection function
*/

LUA_API int lua_gc(lua_State* L, int what, int data)
{
	int res = 0;
	global_State* g;
	lua_lock(L);
	g = G(L);
	switch (what)
	{
	case LUA_GCSTOP:
		{
			g->gcrunning = 0;
			break;
		}
	case LUA_GCRESTART:
		{
			luaE_setdebt(g, 0);
			g->gcrunning = 1;
			break;
		}
	case LUA_GCCOLLECT:
		{
			luaC_fullgc(L, 0);
			break;
		}
	case LUA_GCCOUNT:
		{
			/* GC values are expressed in Kbytes: #bytes/2^10 */
			res = cast_int(gettotalbytes(g) >> 10);
			break;
		}
	case LUA_GCCOUNTB:
		{
			res = cast_int(gettotalbytes(g) & 0x3ff);
			break;
		}
	case LUA_GCSTEP:
		{
			l_mem debt = 1; /* =1 to signal that it did an actual step */
			lu_byte oldrunning = g->gcrunning;
			g->gcrunning = 1; /* allow GC to run */
			if (data == 0)
			{
				luaE_setdebt(g, -GCSTEPSIZE); /* to do a "small" step */
				luaC_step(L);
			}
			else
			{
				/* add 'data' to total debt */
				debt = cast(l_mem, data) * 1024 + g->GCdebt;
				luaE_setdebt(g, debt);
				luaC_checkGC(L);
			}
			g->gcrunning = oldrunning; /* restore previous state */
			if (debt > 0 && g->gcstate == GCSpause) /* end of cycle? */
				res = 1; /* signal it */
			break;
		}
	case LUA_GCSETPAUSE:
		{
			res = g->gcpause;
			g->gcpause = data;
			break;
		}
	case LUA_GCSETSTEPMUL:
		{
			res = g->gcstepmul;
			if (data < 40) data = 40; /* avoid ridiculous low values (and 0) */
			g->gcstepmul = data;
			break;
		}
	case LUA_GCISRUNNING:
		{
			res = g->gcrunning;
			break;
		}
	default: res = -1; /* invalid option */
	}
	lua_unlock(L);
	return res;
}


/*
** miscellaneous functions
*/


LUA_API int lua_error(lua_State* L)
{
	lua_lock(L);
	api_checknelems(L, 1);
	luaG_errormsg(L);
	/* code unreachable; will unlock when control actually leaves the kernel */
	return 0; /* to avoid warnings */
}


LUA_API int lua_next(lua_State* L, int idx)
{
	StkId t;
	int more;
	lua_lock(L);
	t = index2addr(L, idx);
	api_check(L, ttistable(t), "table expected");
	more = luaH_next(L, hvalue(t), L->top - 1);
	if (more)
	{
		api_incr_top(L);
	}
	else /* no more elements */
		L->top -= 1; /* remove key */
	lua_unlock(L);
	return more;
}


LUA_API void lua_concat(lua_State* L, int n)
{
	lua_lock(L);
	api_checknelems(L, n);
	if (n >= 2)
	{
		luaV_concat(L, n);
	}
	else if (n == 0)
	{
		/* push empty string */
		setsvalue2s(L, L->top, luaS_newlstr(L, "", 0));
		api_incr_top(L);
	}
	/* else n == 1; nothing to do */
	luaC_checkGC(L);
	lua_unlock(L);
}


LUA_API void lua_len(lua_State* L, int idx)
{
	StkId t;
	lua_lock(L);
	t = index2addr(L, idx);
	luaV_objlen(L, L->top, t);
	api_incr_top(L);
	lua_unlock(L);
}


LUA_API lua_Alloc lua_getallocf(lua_State* L, void** ud)
{
	lua_Alloc f;
	lua_lock(L);
	if (ud) *ud = G(L)->ud;
	f = G(L)->frealloc;
	lua_unlock(L);
	return f;
}


LUA_API void lua_setallocf(lua_State* L, lua_Alloc f, void* ud)
{
	lua_lock(L);
	G(L)->ud = ud;
	G(L)->frealloc = f;
	lua_unlock(L);
}


LUA_API void* lua_newuserdata(lua_State* L, size_t size)
{
	Udata* u;
	lua_lock(L);
	u = luaS_newudata(L, size);
	setuvalue(L, L->top, u);
	api_incr_top(L);
	luaC_checkGC(L);
	lua_unlock(L);
	return getudatamem(u);
}


static const char* aux_upvalue(StkId fi, int n, TValue** val,
                               CClosure** owner, UpVal** uv)
{
	switch (ttype(fi))
	{
	case LUA_TCCL:
		{
			/* C closure */
			CClosure* f = clCvalue(fi);
			if (!(1 <= n && n <= f->nupvalues)) return NULL;
			*val = &f->upvalue[n - 1];
			if (owner) *owner = f;
			return "";
		}
	case LUA_TLCL:
		{
			/* Lua closure */
			LClosure* f = clLvalue(fi);
			TString* name;
			Proto* p = f->p;
			if (!(1 <= n && n <= p->sizeupvalues)) return NULL;
			*val = f->upvals[n - 1]->v;
			if (uv) *uv = f->upvals[n - 1];
			name = p->upvalues[n - 1].name;
			return (name == NULL) ? "(*no name)" : getstr(name);
		}
	default: return NULL; /* not a closure */
	}
}


LUA_API const char* lua_getupvalue(lua_State* L, int funcindex, int n)
{
	const char* name;
	TValue* val = NULL; /* to avoid warnings */
	lua_lock(L);
	name = aux_upvalue(index2addr(L, funcindex), n, &val, NULL, NULL);
	if (name)
	{
		setobj2s(L, L->top, val);
		api_incr_top(L);
	}
	lua_unlock(L);
	return name;
}


LUA_API const char* lua_setupvalue(lua_State* L, int funcindex, int n)
{
	const char* name;
	TValue* val = NULL; /* to avoid warnings */
	CClosure* owner = NULL;
	UpVal* uv = NULL;
	StkId fi;
	lua_lock(L);
	fi = index2addr(L, funcindex);
	api_checknelems(L, 1);
	name = aux_upvalue(fi, n, &val, &owner, &uv);
	if (name)
	{
		L->top--;
		setobj(L, val, L->top);
		if (owner) { luaC_barrier(L, owner, L->top); }
		else if (uv) { luaC_upvalbarrier(L, uv); }
	}
	lua_unlock(L);
	return name;
}


static UpVal** getupvalref(lua_State* L, int fidx, int n, LClosure** pf)
{
	LClosure* f;
	StkId fi = index2addr(L, fidx);
	api_check(L, ttisLclosure(fi), "Lua function expected");
	f = clLvalue(fi);
	api_check(L, (1 <= n && n <= f->p->sizeupvalues), "invalid upvalue index");
	if (pf) *pf = f;
	return &f->upvals[n - 1]; /* get its upvalue pointer */
}


LUA_API void* lua_upvalueid(lua_State* L, int fidx, int n)
{
	StkId fi = index2addr(L, fidx);
	switch (ttype(fi))
	{
	case LUA_TLCL:
		{
			/* lua closure */
			return *getupvalref(L, fidx, n, NULL);
		}
	case LUA_TCCL:
		{
			/* C closure */
			CClosure* f = clCvalue(fi);
			api_check(L, 1 <= n && n <= f->nupvalues, "invalid upvalue index");
			return &f->upvalue[n - 1];
		}
	default:
		{
			api_check(L, 0, "closure expected");
			return NULL;
		}
	}
}


LUA_API void lua_upvaluejoin(lua_State* L, int fidx1, int n1,
                             int fidx2, int n2)
{
	LClosure* f1;
	UpVal** up1 = getupvalref(L, fidx1, n1, &f1);
	UpVal** up2 = getupvalref(L, fidx2, n2, NULL);
	luaC_upvdeccount(L, *up1);
	*up1 = *up2;
	(*up1)->refcount++;
	if (upisopen(*up1)) (*up1)->u.open.touched = 1;
	luaC_upvalbarrier(L, *up1);
}