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inline BOOL Base64Encode(
const BYTE *pbSrcData,
int nSrcLen,
LPSTR szDest,
int *pnDestLen,
DWORD dwFlags = ATL_BASE64_FLAG_NONE) throw()
{
static const char s_chBase64EncodingTable[64] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q',
'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y',
'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };
if (!pbSrcData || !szDest || !pnDestLen)
{
return FALSE;
}
if(*pnDestLen < Base64EncodeGetRequiredLength(nSrcLen, dwFlags))
{
return FALSE;
}
int nWritten( 0 );
int nLen1( (nSrcLen/3)*4 );
int nLen2( nLen1/76 );
int nLen3( 19 );
for (int i=0; i<=nLen2; i++)
{
if (i==nLen2)
nLen3 = (nLen1%76)/4;
for (int j=0; j<nLen3; j++)
{
DWORD dwCurr(0);
for (int n=0; n<3; n++)
{
dwCurr |= *pbSrcData++;
dwCurr <<= 8;
}
for (int k=0; k<4; k++)
{
BYTE b = (BYTE)(dwCurr>>26);
// BUG在这,windows上的原文件没有下面这句,这是我加的,不加的话,b的高两位会是前面的bit,
// 导致b的大小可能超过数组大小64,产生不可预知的错误
b &= 0b00111111;
*szDest++ = s_chBase64EncodingTable[b];
dwCurr <<= 6;
}
}
nWritten+= nLen3*4;
if ((dwFlags & ATL_BASE64_FLAG_NOCRLF)==0)
{
*szDest++ = '\r';
*szDest++ = '\n';
nWritten+= 2;
}
}
if (nWritten && (dwFlags & ATL_BASE64_FLAG_NOCRLF)==0)
{
szDest-= 2;
nWritten -= 2;
}
nLen2 = (nSrcLen%3) ? (nSrcLen%3 + 1) : 0;
if (nLen2)
{
DWORD dwCurr(0);
for (int n=0; n<3; n++)
{
if (n<(nSrcLen%3))
dwCurr |= *pbSrcData++;
dwCurr <<= 8;
}
for (int k=0; k<nLen2; k++)
{
BYTE b = (BYTE)(dwCurr>>26);
*szDest++ = s_chBase64EncodingTable[b];
dwCurr <<= 6;
}
nWritten+= nLen2;
if ((dwFlags & ATL_BASE64_FLAG_NOPAD)==0)
{
nLen3 = nLen2 ? 4-nLen2 : 0;
for (int j=0; j<nLen3; j++)
{
*szDest++ = '=';
}
nWritten+= nLen3;
}
}
*pnDestLen = nWritten;
return TRUE;
}