Re: CryptBinaryToString and CryptStringToBinary

From:
"Alex Blekhman" <tkfx.REMOVE@yahoo.com>
Newsgroups:
microsoft.public.vc.language
Date:
Thu, 20 Nov 2008 11:25:24 +0200
Message-ID:
<emkvsHvSJHA.3668@TK2MSFTNGP03.phx.gbl>
"Carl Forsman" wrote:

why this code does not work?

I used the CryptStringToBinary function to save the Base64
string to a binary image file (test.png)

http://www.oniva.com/upload/1356/test.cpp


I don't know why does not work. It won't even compile. For
starters, you allocate an array of bytes with the size 1 byte. I
am in doubt that this array will be sufficient to hold the result
of conversion. I tried this code and it works for me:

#include <vector>
#include <algorithm>
#include <fstream>
#include <iterator>

int _tmain(int /*argc*/, _TCHAR* /*argv*/[])
{
    LPCTSTR pszBase64 = _T("<base64 string goes here>");

    // calculate the length of the buffer needed
    //
    DWORD cbBinary = 0;
    BOOL bRet = CryptStringToBinary(
        pszBase64,
        _tcslen(pszBase64),
        CRYPT_STRING_BASE64,
        NULL,
        &cbBinary,
        NULL,
        NULL);

    if(bRet)
    {
        vector<BYTE> vecBin(cbBinary);

        // decode base64 to binary
        //
        bRet = CryptStringToBinary(
            pszBase64,
            _tcslen(pszBase64),
            CRYPT_STRING_BASE64,
            &vecBin[0],
            &cbBinary,
            NULL,
            NULL);

        if(bRet)
        {
            // save decoded data
            //
            ofstream ofsPng(_T("test.png"),
                ios_base::out | ios_base::binary);

            if(!ofsPng.bad())
            {
                copy(vecBin.begin(), vecBin.end(),
                    ostream_iterator<BYTE>(ofsPng));
            }
        }
    }

    return 0;
}

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