Bit Mask技术

#define __LEOPARD_BOOK_MAX_BYTES__ (__LEOPARD_BOOK_MAX_ROWS__* __LEOPARD_BOOK_MAX_COLS__)
U8 Book_Mask[(((U32)__LEOPARD_BOOK_MAX_BYTES__) / 8) + 1];
const S32 book_max_bytes = ((U32)__LEOPARD_BOOK_MAX_BYTES__);

#define BOOK_ARRAY_SET_BIT_MASK(_mask, _index)  (_mask[_index / 8] |= (1 << (_index % 8)))
#define BOOK_ARRAY_CLEAR_BIT_MASK(_mask, _index)  (_mask[_index / 8] &= ~(1 << (_index % 8)))
#define BOOK_ARRAY_IS_BIT_MASK(_mask, _index)  ((_mask[_index / 8] >> (_index & 0x7)) & 0x1)

void Hide_Char_By_Index(U8* ItemMask,U32 index)
{
    U16 idx = 0, reminding = 0;
	
    if (index < book_max_bytes)
    {
        idx = index / 8;
        reminding = index - (idx * 8);
        *(ItemMask+idx) |= (1 << (7 - reminding));
    }
}

void Unhide_Char_By_Index(U8* ItemMask,U32 index)
{
    U16 idx = 0, reminding = 0;
	
    if (index < book_max_bytes)
    {
        idx = index / 8;
        reminding = index - (idx * 8);
        *(ItemMask+idx) &= ~(1 << (7 - reminding));
   }
}

bool Is_Char_Hidden_By_Index(U8* ItemMask,U32 index)
{
    return ((ItemMask[index / 8] >> (index & 0x7)) & 0x1);
}