lua拡張ライブラリlpackの使用ガイドラインについて

luaopen_pack(lua_state);

require("lpack")

--luapack         
local _ss = luapack(">P", "  asd")

local _ss2 = luapack(">h", 500)
_ss = _ss.._ss2
print(_ss, #_ss)

--    
  asd        9
  asd       11

--luaunpack         
--    1
local ne, value = luaunpack(_ss, ">P")
print(ne, value)

_ss = string.sub(_ss, ne, #_ss)
local ne, value = luaunpack(_ss, ">h")
print(ne, value)

--    
10        asd
3       500

--    2
local ne, value1, value2 = luaunpack(_ss, ">Ph")
print(ne, value, value2)

--    
12        asd 500

    #define OP_ZSTRING  'z'     //    
    #define OP_BSTRING  'p'     //    2^8    
    #define OP_WSTRING  'P'     //    2^16    
    #define OP_SSTRING  'a'     //    2^32/64    */
    #define OP_STRING   'A'     //       
    #define OP_FLOAT    'f'     /* float */
    #define OP_DOUBLE   'd'     /* double */
    #define OP_NUMBER   'n'     /* Lua number */
    #define OP_CHAR     'c'     /* char */
    #define OP_BYTE     'b'     /* byte = unsigned char */
    #define OP_SHORT    'h'     /* short */
    #define OP_USHORT   'H'     /* unsigned short */
    #define OP_INT      'i'     /* int */
    #define OP_UINT     'I'     /* unsigned int */
    #define OP_LONG     'l'     /* long */
    #define OP_ULONG    'L'     /* unsigned long */