296   size_t pos = luaL_optinteger(L, 3, 1);  in b_unpack()  local
297   luaL_argcheck(L, pos > 0, 3, "offset must be 1 or greater");  in b_unpack()
298   pos--; /* Lua indexes are 1-based, but here we want 0-based for C  in b_unpack()
305     pos += gettoalign(pos, &h, opt, size);  in b_unpack()
306     luaL_argcheck(L, size <= ld && pos <= ld - size,  in b_unpack()
314         lua_Number res = getinteger(data+pos, h.endian, issigned, size);  in b_unpack()
323         memcpy(&f, data+pos, size);  in b_unpack()
330         memcpy(&d, data+pos, size);  in b_unpack()
341           luaL_argcheck(L, size <= ld && pos <= ld - size,  in b_unpack()
344         lua_pushlstring(L, data+pos, size); n++;  in b_unpack()
348         const char *e = (const char *)memchr(data+pos, '\0', ld - pos);  in b_unpack()
351         size = (e - (data+pos)) + 1;  in b_unpack()
352         lua_pushlstring(L, data+pos, size - 1); n++;  in b_unpack()
357     pos += size;  in b_unpack()
359   lua_pushinteger(L, pos + 1);  /* next position */  in b_unpack()
367   size_t pos = 0;  in b_size()  local
372     pos += gettoalign(pos, &h, opt, size);  in b_size()
379     pos += size;  in b_size()
381   lua_pushinteger(L, pos);  in b_size()