utf-7与UNICODE的转换。

在处理IMAP4时，发现从服务器发送过来的消息，是用UTF7进行编码的。

字符串形如

&XfJT0ZABkK5O9g-

这是一种UTF-7的编码，在进行处理时，需要将其首字母&改为+

变成

+XfJT0ZABkK5O9g-

然后进行转换，转换的代码如下。

1、C++代码

CString Convert(CString str, int sourceCodepage, int targetCodepage)

{

int len = str.GetLength();

int unicodeLen = MultiByteToWideChar(sourceCodepage, 0, str, -1, NULL, 0);

wchar_t *pUnicode = new wchar_t[unicodeLen + 1];

memset(pUnicode, 0, (unicodeLen + 1) * sizeof(wchar_t));

MultiByteToWideChar(sourceCodepage, 0, str, -1, (LPWSTR)pUnicode, unicodeLen);//61 00 11 62 62 00 00 00

BYTE *pTargetData = NULL;

int targetLen = WideCharToMultiByte(targetCodepage, 0, (LPWSTR)pUnicode, -1, (char *)pTargetData, 0, NULL, NULL);

pTargetData = new BYTE[targetLen + 1];

memset(pTargetData, 0, targetLen + 1);

WideCharToMultiByte(targetCodepage, 0, (LPWSTR)pUnicode, -1, (char *)pTargetData, targetLen, NULL, NULL);//61 e6 88 91 62 00

CString rt;

rt.Format("%s", pTargetData);

delete pUnicode;

delete pTargetData;

return rt;

}

2、DELPHI代码

function Convert(str: string; sourceCodepage: Cardinal; targetCodepage: Cardinal): string;

var

Len: Integer;

UnicodeLen: Integer;

pUnicode: PWideChar;

pTargetData: PChar;

targetLen: Integer;

begin

Len := Length(str);

UnicodeLen := MultiByteToWideChar(sourceCodepage, 0, PAnsiChar(str), -1, nil, 0);

GetMem(pUnicode, (UnicodeLen + 1) * SizeOf(WideChar));

ZeroMemory(pUnicode, (UnicodeLen + 1) * SizeOf(WideChar));

MultiByteToWideChar(sourceCodepage, 0, PAnsiChar(str), -1, pUnicode, unicodeLen);//61 00 11 62 62 00 00 00

pTargetData := nil;

targetLen := WideCharToMultiByte(targetCodepage, 0, PWideChar(pUnicode), -1, pTargetData, 0, nil, nil);

GetMem(pTargetData, targetLen + 1);

ZeroMemory(pTargetData, targetLen + 1);

WideCharToMultiByte(targetCodepage, 0, PWideChar(pUnicode), -1, pTargetData, targetLen, nil, nil);//61 e6 88 91 62 00

Result := Copy(PTargetData, 1, Length(pTargetData));

FreeMem(pTargetData);

FreeMem(pUnicode);

end;