/* 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; }