如何将二进制字符串转换为 base64 编码的数据

Question

I am receiving binary data in a string. I want to encode that into Base64. Is there any class to do that operation (I want an API).

Answer 1

CryptBinaryToString ...if you target to Windows platform

Here is a little sample:

#include <Windows.h>

#pragma comment(lib, "crypt32.lib")

int main()
{
    LPCSTR pszSource = "Man is distinguished, not only by his reason, but ...";
    DWORD nDestinationSize;
    if (CryptBinaryToString(reinterpret_cast<const BYTE*> (pszSource), strlen(pszSource), CRYPT_STRING_BASE64, nullptr, &nDestinationSize))
    {
        LPTSTR pszDestination = static_cast<LPTSTR> (HeapAlloc(GetProcessHeap(), HEAP_NO_SERIALIZE, nDestinationSize * sizeof(TCHAR)));
        if (pszDestination)
        {
            if (CryptBinaryToString(reinterpret_cast<const BYTE*> (pszSource), strlen(pszSource), CRYPT_STRING_BASE64, pszDestination, &nDestinationSize))
            {
                // Succeeded: 'pszDestination' is 'pszSource' encoded to base64.
            }
            HeapFree(GetProcessHeap(), HEAP_NO_SERIALIZE, pszDestination);
        }
    }
    return 0;
}

Answer 2

A quick google search for c++ base64 gives you these links:
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