static TString *LoadString (LoadState *S) {
size_t size = LoadByte(S);
if (size == 0xFF)
LoadVar(S, size);
if (size == 0)
return NULL;
else if (--size <= LUAI_MAXSHORTLEN) { /* short string? */
char buff[LUAI_MAXSHORTLEN];
LoadVector(S, buff, size);
return luaS_newlstr(S->L, buff, size);
}
else { /* long string */
TString *ts = luaS_createlngstrobj(S->L, size);
LoadVector(S, getstr(ts), size); /* load directly in final place */
return ts;
}
}
/*
** 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 */
}
