添加项目文件。

Base64Img/Base64Img.cpp

@@ -0,0 +1,34 @@
+// Base64Img.cpp : 定义 DLL 应用程序的导出函数。
+//
+
+#include "stdafx.h"
+#include "Base64Img.h"
+
+LPSTR StreamToBase64 (HISTREAM ifile)
+{
+	if (!ifile) return NULL;
+	IStream *pStream = (IStream *)ifile;
+	LARGE_INTEGER liZero = {};
+	pStream->Seek (liZero, STREAM_SEEK_SET, nullptr);
+	STATSTG statstg;
+	pStream->Stat (&statstg, STATFLAG_NONAME);
+	ULARGE_INTEGER uliSize = statstg.cbSize;
+	std::vector<BYTE> buffer (uliSize.QuadPart);
+	ULONG bytesRead;
+	pStream->Read (buffer.data (), static_cast<ULONG>(buffer.size ()), &bytesRead);
+	DWORD base64Size = 0;
+	if (!CryptBinaryToStringA (buffer.data (), bytesRead, CRYPT_STRING_BASE64 | CRYPT_STRING_NOCRLF, nullptr, &base64Size))
+	{
+		return NULL;
+	}
+	std::vector<char> base64Buffer (base64Size);
+	if (!CryptBinaryToStringA (buffer.data (), bytesRead, CRYPT_STRING_BASE64 | CRYPT_STRING_NOCRLF, base64Buffer.data (), &base64Size))
+	{
+		return NULL;
+	}
+	std::string res = std::string (base64Buffer.begin (), base64Buffer.end ());
+	LPSTR lpszStr = (LPSTR)calloc (res.capacity (), sizeof (char));
+	if (!lpszStr) return NULL;
+	lstrcpyA (lpszStr, res.c_str ());
+	return lpszStr;
+}