Add pk_context and associated functions
diff --git a/library/pk.c b/library/pk.c
new file mode 100644
index 0000000..a5f8d6b
--- /dev/null
+++ b/library/pk.c
@@ -0,0 +1,93 @@
+/*
+ * Public Key abstraction layer
+ *
+ * Copyright (C) 2006-2013, Brainspark B.V.
+ *
+ * This file is part of PolarSSL (http://www.polarssl.org)
+ * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "polarssl/config.h"
+
+#include "polarssl/rsa.h"
+#include "polarssl/ecp.h"
+#include "polarssl/pk.h"
+
+#include <stdlib.h>
+
+/*
+ * Initialise a pk_context
+ */
+void pk_init( pk_context *ctx )
+{
+ if( ctx == NULL )
+ return;
+
+ ctx->type = POLARSSL_PK_NONE;
+ ctx->data = NULL;
+}
+
+/*
+ * Free (the components of) a pk_context
+ */
+void pk_free( pk_context *ctx )
+{
+ if( ctx == NULL )
+ return;
+
+ switch( ctx->type )
+ {
+ case POLARSSL_PK_NONE:
+ break;
+
+ case POLARSSL_PK_RSA:
+ rsa_free( ctx->data );
+ break;
+
+ case POLARSSL_PK_ECKEY:
+ case POLARSSL_PK_ECKEY_DH:
+ ecp_keypair_free( ctx->data );
+ break;
+ }
+
+ ctx->type = POLARSSL_PK_NONE;
+ ctx->data = NULL;
+}
+
+/*
+ * Set a pk_context to a given type
+ */
+int pk_set_type( pk_context *ctx, pk_type_t type )
+{
+ size_t size = type == POLARSSL_PK_RSA ? sizeof( rsa_context )
+ : type == POLARSSL_PK_ECKEY ? sizeof( ecp_keypair )
+ : type == POLARSSL_PK_ECKEY_DH ? sizeof( ecp_keypair )
+ : 0;
+
+ if( size == 0 )
+ return( 0 );
+
+ if( ( ctx->data = malloc( size ) ) == NULL )
+ return( -1 );
+
+ memset( ctx->data, 0, size );
+ ctx->type = type;
+
+ return( 0 );
+}
