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在WPARAM中组合5个值

bit-manipulation mfc

Andrew Truckle · 技术社区 · 7 年前

我几年前写过这段代码:

int CAssignSelectedColumnDlg::RegistryIntFromData(int iColumnIndex, int iCustomIndex, BOOL bAvoidConflicts, int iNumMeetings)
{
    WORD    wLowWord = MAKEWORD(iColumnIndex, iCustomIndex);
    WORD    wHighWord = MAKEWORD(bAvoidConflicts ? 1 : 0, iNumMeetings);

    return (int)MAKEWPARAM(wLowWord, wHighWord);
}

现在我重温一下这段代码。我需要介绍第五个数字 BOOL 0/1. 这可能吗?

1 回复 | 直到 7 年前

Barmak Shemirani 7 年前

请注意 iColumnIndex , iCustomIndex 和 iNumMeetings 不能超过 255 ,应该是 BYTE . 您可以添加更多 BOOL 中的值 lobyte 属于 hiword . 返回值应为 unsigned int . 为了向后兼容,您可能应该将返回值保留为 int .

int foo(int iColumnIndex, int iCustomIndex,
    BOOL bAvoidConflicts, int iNumMeetings, BOOL bFifth)
{
    bAvoidConflicts = !!bAvoidConflicts;
    bFifth = !!bFifth;

    WORD loword = MAKEWORD(iColumnIndex, iCustomIndex);

    BYTE lobyte = (BYTE)(bAvoidConflicts << 0) | (BYTE)(bFifth << 1);
    BYTE hibyte = (BYTE)iNumMeetings;
    WORD hiword = MAKEWORD(lobyte, hibyte);

    return (int)MAKEWPARAM(loword, hiword);
}

并检查值:

unsigned int res = foo(x1, x2, x3, x4, x5);

WORD loword = LOWORD(res);
WORD hiword = HIWORD(res);

BYTE iColumnIndex = LOBYTE(loword);
BYTE iCustomIndex = HIBYTE(loword);
BYTE lobyte       = LOBYTE(hiword);
BYTE iNumMeetings = HIBYTE(hiword);

BOOL bAvoidConflicts = !!(lobyte & 1);
BOOL bFifth = !!(lobyte & 2);

if(x1 != iColumnIndex) printf("error 1\n");
if(x2 != iCustomIndex) printf("error 2\n");
if(x3 != bAvoidConflicts) printf("error 3\n");
if(x4 != iNumMeetings) printf("error 4\n");
if(x5 != bFifth) printf("error 5\n");

当然,如果只使用结构并将值存储为 内景 , bool 等

这里有一个不同的版本来添加更多的位,或者强制一个表示新版本的位。

这些名字现在令人困惑。 bFifth 是第五个参数,是第二位 (bit1 << 1)

bit2 (第三位!)对于新版本,设置为1

int foo(int iColumnIndex, int iCustomIndex,
    BOOL bAvoidConflicts, int iNumMeetings, BOOL bFifth)
{
    bAvoidConflicts = !!bAvoidConflicts;
    bFifth = !!bFifth;

    WORD loword = MAKEWORD(iColumnIndex, iCustomIndex);

    BOOL bit0 = bAvoidConflicts;
    BOOL bit1 = bFifth;
    BOOL bit2 = 1; //<-- always 1 to indicate new version

    BYTE lobyte = 0;
    lobyte |= (BYTE)(bit0 << 0);
    lobyte |= (BYTE)(bit1 << 1);
    lobyte |= (BYTE)(bit2 << 2);
    //lobyte |= (BYTE)(bit3 << 3);
    //lobyte |= (BYTE)(bit4 << 4);
    //lobyte |= (BYTE)(bit5 << 5);
    //lobyte |= (BYTE)(bit6 << 6);
    //lobyte |= (BYTE)(bit7 << 7);

    WORD hiword = MAKEWORD(lobyte, iNumMeetings);

    return (int)MAKEWPARAM(loword, hiword);
}

检查方法与之前相同

int res = foo(255, 254, 1, 253, 1);

WORD loword = LOWORD(res);
WORD hiword = HIWORD(res);

BYTE iColumnIndex = LOBYTE(loword);
BYTE iCustomIndex = HIBYTE(loword);
BYTE iNumMeetings = HIBYTE(hiword);
BYTE lobyte       = LOBYTE(hiword);

BOOL b0 = !!(lobyte & 1);  //bAvoidConflicts
BOOL b1 = !!(lobyte & 2);  //bFifth
BOOL b2 = !!(lobyte & 4);  //version check
BOOL b3 = !!(lobyte & 8);  //not used
BOOL b4 = !!(lobyte & 16); //not used
BOOL b5 = !!(lobyte & 32); //not used
BOOL b6 = !!(lobyte & 64); //not used
BOOL b7 = !!(lobyte & 128);//not used