Memcpy无法使用unicode [英] Memcpy is not working in unicode

问题描述

无法在unicode模式下将数据从m_pdata复制到pdata。



m_pdata - LPBTYE

pdata- LPTSTR
nlen =是m_pdata的长度



void CXTest :: Load（CString& val）

{

LPTSTR pBuffer = val.GetBuffer（val.getlength（）+ 1）;

memcpy（pdata，m_pdata，nLen）;

pdata [nLen] = _T（'\ 0'）;

val.ReleaseBuffer（）;

}

pdata正在获得垃圾值。





请告诉我它为什么不工作。



我尝试过：



m_pdata有数据



LPTSTR pBuffer = val。 GetBuffer（val.getlength（）+ 1）;

memcpy（pdata，m_pdata，nLen）;

pdata [nLen] = _T（'\0'）;

val.ReleaseBuffer（）;

Not able to copy data from m_pdata to pdata in the unicode mode.

m_pdata - LPBTYE
pdata- LPTSTR
nlen = is length of m_pdata

void CXTest::Load(CString &val)
{
LPTSTR pBuffer = val.GetBuffer(val.getlength() + 1);
memcpy(pdata, m_pdata, nLen);
pdata[nLen] = _T('\0');
val.ReleaseBuffer();
}
pdata is getting junk value.


Please let me know why it is not working.

What I have tried:

m_pdata is having data

LPTSTR pBuffer = val.GetBuffer(val.getlength() + 1);
memcpy(pdata, m_pdata, nLen);
pdata[nLen] = _T('\0');
val.ReleaseBuffer();

推荐答案

当你有 nLen 字节时 m_pdata 这些不是Unicode字符，而是一些ki nd的ANSI / ASCII字符，你想创建一个Unicode字符串，使用 MultiByteToWideChar功能（Windows） [ ^ ]：

When you have nLen bytes in m_pdata that are not Unicode characters but some kind of ANSI / ASCII characters and you want to create a Unicode string from those use the MultiByteToWideChar function (Windows)[^]:

if (nLen < nWideSize - 1)
{
    MultiByteToWideChar(nCodePage, 0, (LPCSTR)m_pdata, nLen, pdata, nWideSize);
    pdata[nLen] = _T('\0');
}

其中

nCodePage =中的字符编码 m_pdata

nWideSize = pdata的大小字符缓冲区



当字节为ASCII时，使用代码页20127.对于其他代码页，请参阅代码页标识符（Windows） [ ^ ]。

where
nCodePage = the encoding of the characters in m_pdata
nWideSize = the size of the pdata buffer in characters

When the bytes are ASCII, use code page 20127. For other code pages see Code Page Identifiers (Windows)[^].

更新版本的MFC使用ATL的CString类 - 可以在ANSI和Unicode之间进行转换。



如何：在各种字符串类型之间进行转换 [ ^ ]



就像TCHAR一样是char或wchar_t，CString实际上可能是CStringA或CStringW。无论哪种情况，将const char *分配给CStringA或CStringW都可以正常工作 - 如上面的MSDN文章所示。



这是我的假设：

The more recent versions of MFC use the CString classes from ATL - which can convert between ANSI and Unicode.

How to: Convert Between Various String Types[^]

Just as TCHAR may be char or wchar_t, CString may actually be CStringA or CStringW. In either case, assigning a const char * to a CStringA or CStringW just works - as shown by the MSDN article above.

Here's my assumptions:

class CXTest
{
    unsigned char m_pdata[1024]; // pointer to byte?
    unsigned nLen;

    void Load(CString &val);
};

如果您的字符串是nul终止，这将有效。

If your string is nul terminated, this would work.

void CXTest::Load(CString &val)
{
    const char *text = (const char *)m_pdata;
    val = text;
}

你的文字有一个长度所以你可能想要这个：

Your text has a length so you probably want this:

void CXTest::Load(CString &val)
{
    const char *text = (const char *)m_pdata;
    CString load(text, nLen);
    val = load;
}

这篇关于Memcpy无法使用unicode的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！