/* copy strings in stack from top - n up to top - 1 to buffer */
static void copy2buff (StkId top, int n, char *buff) {
size_t tl = 0; /* size already copied */
do {
size_t l = vslen(top - n); /* length of string being copied */
memcpy(buff + tl, svalue(top - n), l * sizeof(char));
tl += l;
} while (--n > 0);
}
/*
** Main operation for concatenation: concat 'total' values in the stack,
** from 'L->top - total' up to 'L->top - 1'.
*/
void luaV_concat (lua_State *L, int total) {
lua_assert(total >= 2);
do {
StkId top = L->top;
int n = 2; /* number of elements handled in this pass (at least 2) */
if (!(ttisstring(top-2) || cvt2str(top-2)) || !tostring(L, top-1))
luaT_trybinTM(L, top-2, top-1, top-2, TM_CONCAT);
else if (isemptystr(top - 1)) /* second operand is empty? */
cast_void(tostring(L, top - 2)); /* result is first operand */
else if (isemptystr(top - 2)) { /* first operand is an empty string? */
setobjs2s(L, top - 2, top - 1); /* result is second op. */
}
else {
/* at least two non-empty string values; get as many as possible */
size_t tl = vslen(top - 1);
TString *ts;
/* collect total length and number of strings */
for (n = 1; n < total && tostring(L, top - n - 1); n++) {
size_t l = vslen(top - n - 1);
if (l >= (MAX_SIZE/sizeof(char)) - tl)
luaG_runerror(L, "string length overflow");
tl += l;
}
if (tl <= LUAI_MAXSHORTLEN) { /* is result a short string? */
char buff[LUAI_MAXSHORTLEN];
copy2buff(top, n, buff); /* copy strings to buffer */
ts = luaS_newlstr(L, buff, tl);
}
else { /* long string; copy strings directly to final result */
ts = luaS_createlngstrobj(L, tl);
copy2buff(top, n, getstr(ts));
}
setsvalue2s(L, top - n, ts); /* create result */
}
total -= n-1; /* got 'n' strings to create 1 new */
L->top -= n-1; /* popped 'n' strings and pushed one */
} while (total > 1); /* repeat until only 1 result left */
}
/*
** Try to convert a value to a float. The float case is already handled
** by the macro 'tonumber'.
*/
int luaV_tonumber_ (const TValue *obj, lua_Number *n) {
TValue v;
if (ttisinteger(obj)) {
*n = cast_num(ivalue(obj));
return 1;
}
else if (cvt2num(obj) && /* string convertible to number? */
luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
*n = nvalue(&v); /* convert result of 'luaO_str2num' to a float */
return 1;
}
else
return 0; /* conversion failed */
}
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 */
luaC_checkGC(L);
o = index2addr(L, idx); /* previous call may reallocate the stack */
luaO_tostring(L, o);
lua_unlock(L);
}
if (len != NULL)
*len = vslen(o);
return svalue(o);
}
/*
** try to convert a value to an integer, rounding according to 'mode':
** mode == 0: accepts only integral values
** mode == 1: takes the floor of the number
** mode == 2: takes the ceil of the number
*/
int luaV_tointeger (const TValue *obj, lua_Integer *p, int mode) {
TValue v;
again:
if (ttisfloat(obj)) {
lua_Number n = fltvalue(obj);
lua_Number f = l_floor(n);
if (n != f) { /* not an integral value? */
if (mode == 0) return 0; /* fails if mode demands integral value */
else if (mode > 1) /* needs ceil? */
f += 1; /* convert floor to ceil (remember: n != f) */
}
return lua_numbertointeger(f, p);
}
else if (ttisinteger(obj)) {
*p = ivalue(obj);
return 1;
}
else if (cvt2num(obj) &&
luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
obj = &v;
goto again; /* convert result from 'luaO_str2num' to an integer */
}
return 0; /* conversion failed */
}
/*
** try to convert a value to an integer, rounding according to 'mode':
** mode == 0: accepts only integral values
** mode == 1: takes the floor of the number
** mode == 2: takes the ceil of the number
*/
int luaV_tointeger (const TValue *obj, lua_Integer *p, int mode) {
TValue v;
again:
#ifndef _KERNEL
if (ttisfloat(obj)) {
lua_Number n = fltvalue(obj);
lua_Number f = l_floor(n);
if (n != f) { /* not an integral value? */
if (mode == 0) return 0; /* fails if mode demands integral value */
else if (mode > 1) /* needs ceil? */
f += 1; /* convert floor to ceil (remember: n != f) */
}
return lua_numbertointeger(f, p);
}
else if (ttisinteger(obj)) {
#else /* _KERNEL */
if (ttisinteger(obj)) {
UNUSED(mode);
#endif
*p = ivalue(obj);
return 1;
}
else if (cvt2num(obj) &&
luaO_str2num(svalue(obj), &v) == vslen(obj) + 1) {
obj = &v;
goto again; /* convert result from 'luaO_str2num' to an integer */
}
return 0; /* conversion failed */
}
#ifndef _KERNEL
/*
** Try to convert a 'for' limit to an integer, preserving the
** semantics of the loop.
** (The following explanation assumes a non-negative step; it is valid
** for negative steps mutatis mutandis.)
** If the limit can be converted to an integer, rounding down, that is
** it.
** Otherwise, check whether the limit can be converted to a number. If
** the number is too large, it is OK to set the limit as LUA_MAXINTEGER,
** which means no limit. If the number is too negative, the loop
** should not run, because any initial integer value is larger than the
** limit. So, it sets the limit to LUA_MININTEGER. 'stopnow' corrects
** the extreme case when the initial value is LUA_MININTEGER, in which
** case the LUA_MININTEGER limit would still run the loop once.
*/
static int forlimit (const TValue *obj, lua_Integer *p, lua_Integer step,
int *stopnow) {
*stopnow = 0; /* usually, let loops run */
if (!luaV_tointeger(obj, p, (step < 0 ? 2 : 1))) { /* not fit in integer? */
lua_Number n; /* try to convert to float */
if (!tonumber(obj, &n)) /* cannot convert to float? */
return 0; /* not a number */
if (luai_numlt(0, n)) { /* if true, float is larger than max integer */
*p = LUA_MAXINTEGER;
if (step < 0) *stopnow = 1;
}
else { /* float is smaller than min integer */
*p = LUA_MININTEGER;
if (step >= 0) *stopnow = 1;
}
}
return 1;
}
