Function str_format

Source/Misc/lua/src/lua.c:14433–14499

static int str_format (lua_State *L) {
int arg = 1;
size_t sfl;
const char *strfrmt = luaL_checklstring(L, arg, &sfl);
const char *strfrmt_end = strfrmt+sfl;
luaL_Buffer b;
luaL_buffinit(L, &b);
while (strfrmt < strfrmt_end) {
if (*strfrmt != L_ESC)
luaL_addchar(&b, *strfrmt++);
else if (*++strfrmt == L_ESC)
luaL_addchar(&b, *strfrmt++);  /* %% */
else { /* format item */
char form[MAX_FORMAT];  /* to store the format (`%...') */
char buff[MAX_ITEM];  /* to store the formatted item */
arg++;
strfrmt = scanformat(L, strfrmt, form);
switch (*strfrmt++) {
case 'c': {
sprintf(buff, form, (int)luaL_checknumber(L, arg));
break;
}
case 'd':  case 'i': {
addintlen(form);
sprintf(buff, form, (LUA_INTFRM_T)luaL_checknumber(L, arg));
break;
}
case 'o':  case 'u':  case 'x':  case 'X': {
addintlen(form);
sprintf(buff, form, (unsigned LUA_INTFRM_T)luaL_checknumber(L, arg));
break;
}
case 'e':  case 'E': case 'f':
case 'g': case 'G': {
sprintf(buff, form, (double)luaL_checknumber(L, arg));
break;
}
case 'q': {
addquoted(L, &b, arg);
continue;  /* skip the 'addsize' at the end */
}
case 's': {
size_t l;
const char *s = luaL_checklstring(L, arg, &l);
if (!strchr(form, '.') && l >= 100) {
/* no precision and string is too long to be formatted;
keep original string */
lua_pushvalue(L, arg);
luaL_addvalue(&b);
continue;  /* skip the `addsize' at the end */
}
else {
sprintf(buff, form, s);
break;
}
}
default: {  /* also treat cases `pnLlh' */
return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "