adding parentheses to macro definitions.

Avoid confusion and possible mistakes in usage of macros.

Signed-off-by: Daniel Otte <d.otte@wut.de>
diff --git a/library/pkwrite.c b/library/pkwrite.c
index f9e598c..a770dfb 100644
--- a/library/pkwrite.c
+++ b/library/pkwrite.c
@@ -455,7 +455,7 @@
  *      publicExponent    INTEGER   -- e            1 + 3 + MPI_MAX + 1
  *  }
  */
-#define RSA_PUB_DER_MAX_BYTES   38 + 2 * MBEDTLS_MPI_MAX_SIZE
+#define RSA_PUB_DER_MAX_BYTES   ( 38 + 2 * MBEDTLS_MPI_MAX_SIZE )
 
 /*
  * RSA private keys:
@@ -474,8 +474,8 @@
  */
 #define MPI_MAX_SIZE_2          ( MBEDTLS_MPI_MAX_SIZE / 2 + \
                                   MBEDTLS_MPI_MAX_SIZE % 2 )
-#define RSA_PRV_DER_MAX_BYTES   47 + 3 * MBEDTLS_MPI_MAX_SIZE \
-                                   + 5 * MPI_MAX_SIZE_2
+#define RSA_PRV_DER_MAX_BYTES   ( 47 + 3 * MBEDTLS_MPI_MAX_SIZE \
+                                   + 5 * MPI_MAX_SIZE_2 )
 
 #else /* MBEDTLS_RSA_C */
 
@@ -496,7 +496,7 @@
  *                                            + 2 * ECP_MAX (coords)    [1]
  *  }
  */
-#define ECP_PUB_DER_MAX_BYTES   30 + 2 * MBEDTLS_ECP_MAX_BYTES
+#define ECP_PUB_DER_MAX_BYTES   ( 30 + 2 * MBEDTLS_ECP_MAX_BYTES )
 
 /*
  * EC private keys:
@@ -507,7 +507,7 @@
  *      publicKey  [1] BIT STRING OPTIONAL      1 + 2 + [1] above
  *    }
  */
-#define ECP_PRV_DER_MAX_BYTES   29 + 3 * MBEDTLS_ECP_MAX_BYTES
+#define ECP_PRV_DER_MAX_BYTES   ( 29 + 3 * MBEDTLS_ECP_MAX_BYTES )
 
 #else /* MBEDTLS_ECP_C */
 
@@ -516,10 +516,10 @@
 
 #endif /* MBEDTLS_ECP_C */
 
-#define PUB_DER_MAX_BYTES   RSA_PUB_DER_MAX_BYTES > ECP_PUB_DER_MAX_BYTES ? \
-                            RSA_PUB_DER_MAX_BYTES : ECP_PUB_DER_MAX_BYTES
-#define PRV_DER_MAX_BYTES   RSA_PRV_DER_MAX_BYTES > ECP_PRV_DER_MAX_BYTES ? \
-                            RSA_PRV_DER_MAX_BYTES : ECP_PRV_DER_MAX_BYTES
+#define PUB_DER_MAX_BYTES   ( RSA_PUB_DER_MAX_BYTES > ECP_PUB_DER_MAX_BYTES ? \
+                              RSA_PUB_DER_MAX_BYTES : ECP_PUB_DER_MAX_BYTES )
+#define PRV_DER_MAX_BYTES   ( RSA_PRV_DER_MAX_BYTES > ECP_PRV_DER_MAX_BYTES ? \
+                              RSA_PRV_DER_MAX_BYTES : ECP_PRV_DER_MAX_BYTES )
 
 int mbedtls_pk_write_pubkey_pem( mbedtls_pk_context *key, unsigned char *buf, size_t size )
 {