Add two new interfaces Pkcs7GetSigners and Pkcs7FreeSigners to BaseCryptLib.

Signed-off by: tye1
Reviewed-by: geekboy15a
Reviewed-by: sfu5
Reviewed-by: gdong1

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13158 6f19259b-4bc3-4df7-8a09-765794883524

CryptoPkg/Library/BaseCryptLib/InternalCryptLib.h

@@ -1,7 +1,7 @@
 /** @file  
   Internal include file for BaseCryptLib.
 
-Copyright (c) 2010, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2010 - 2012, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
 which accompanies this distribution.  The full text of the license may be found at
@@ -28,5 +28,25 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #define OPENSSL_SYSNAME_UWIN
 #endif
 
+/**
+  Pop single certificate from STACK_OF(X509).
+
+  If X509Stack, Cert, or CertSize is NULL, then return FALSE.
+
+  @param[in]  X509Stack       Pointer to a X509 stack object.
+  @param[out] Cert            Pointer to a X509 certificate.
+  @param[out] CertSize        Length of output X509 certificate in bytes.
+                                 
+  @retval     TRUE            The X509 stack pop succeeded.
+  @retval     FALSE           The pop operation failed.
+
+**/
+BOOLEAN
+X509PopCertificate (
+  IN  VOID  *X509Stack,
+  OUT UINT8 **Cert,
+  OUT UINTN *CertSize
+  );
+
 #endif