Function str_split

src/lstrlib.cpp:2015–2060

static int str_split (lua_State *L) {
  /*
    This str_split function is based on the one found in LuaU, licensed under their terms.
    https://github.com/Roblox/luau/blob/master/VM/src/lstrlib.cpp
  */
  size_t haystackLen;
  const char* haystack = luaL_checklstring(L, 1, &haystackLen);
  size_t needleLen;
  const char* needle = luaL_checklstring(L, 2, &needleLen);
  lua_Integer limit = luaL_optinteger(L, 3, LUA_MAXINTEGER) - 1;

  const char* begin = haystack;
  const char* end = haystack + haystackLen;
  const char* spanStart = begin;
  lua_Integer numMatches = 0;

  lua_createtable(L, 0, 0);

  if (needleLen == 0)
    begin++;

  if (l_likely(limit > 0)) {
    for (const char* iter = begin; iter <= end - needleLen; iter++) {
      if (memcmp(iter, needle, needleLen) == 0) {
        lua_pushinteger(L, ++numMatches);
        lua_pushlstring(L, spanStart, iter - spanStart);
        lua_settable(L, -3);
    
        spanStart = iter + needleLen;
        if (needleLen > 0)
          iter += needleLen - 1;
    
        if (numMatches == limit)
          break;
      }
    }
  }

  if (needleLen > 0) {
    lua_pushinteger(L, ++numMatches);
    lua_pushlstring(L, spanStart, end - spanStart);
    lua_settable(L, -3);
  }

  return 1;
}


static int str_islower (lua_State* L) {