Improve style in the Cipher module
diff --git a/library/cipher.c b/library/cipher.c
index b37fc76..abf268f 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -86,7 +86,7 @@
     for( diff = 0, i = 0; i < len; i++ )
         diff |= p1[i] ^ p2[i];
 
-    return (int)diff;
+    return( (int)diff );
 }
 #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */
 
@@ -183,7 +183,7 @@
 {
     CIPHER_VALIDATE_RET( ctx != NULL );
     if( cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) );
 
@@ -216,7 +216,7 @@
     CIPHER_VALIDATE_RET( operation == MBEDTLS_ENCRYPT ||
                          operation == MBEDTLS_DECRYPT );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_KEY_LEN ) == 0 &&
         (int) ctx->cipher_info->key_bitlen != key_bitlen )
@@ -235,13 +235,13 @@
         MBEDTLS_MODE_OFB == ctx->cipher_info->mode ||
         MBEDTLS_MODE_CTR == ctx->cipher_info->mode )
     {
-        return ctx->cipher_info->base->setkey_enc_func( ctx->cipher_ctx, key,
-                ctx->key_bitlen );
+        return( ctx->cipher_info->base->setkey_enc_func( ctx->cipher_ctx, key,
+                                                         ctx->key_bitlen ) );
     }
 
     if( MBEDTLS_DECRYPT == operation )
-        return ctx->cipher_info->base->setkey_dec_func( ctx->cipher_ctx, key,
-                ctx->key_bitlen );
+        return( ctx->cipher_info->base->setkey_dec_func( ctx->cipher_ctx, key,
+                                                         ctx->key_bitlen ) );
 
     return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 }
@@ -255,7 +255,7 @@
     CIPHER_VALIDATE_RET( ctx != NULL );
     CIPHER_VALIDATE_RET( iv_len == 0 || iv != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     /* avoid buffer overflow in ctx->iv */
     if( iv_len > MBEDTLS_MAX_IV_LENGTH )
@@ -297,7 +297,7 @@
 {
     CIPHER_VALIDATE_RET( ctx != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     ctx->unprocessed_len = 0;
 
@@ -311,13 +311,13 @@
     CIPHER_VALIDATE_RET( ctx != NULL );
     CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
 #if defined(MBEDTLS_GCM_C)
     if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
     {
-        return mbedtls_gcm_starts( (mbedtls_gcm_context *) ctx->cipher_ctx, ctx->operation,
-                           ctx->iv, ctx->iv_size, ad, ad_len );
+        return( mbedtls_gcm_starts( (mbedtls_gcm_context *) ctx->cipher_ctx, ctx->operation,
+                                    ctx->iv, ctx->iv_size, ad, ad_len ) );
     }
 #endif
 
@@ -337,8 +337,8 @@
         if ( result != 0 )
             return( result );
 
-        return mbedtls_chachapoly_update_aad( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
-                                                          ad, ad_len );
+        return( mbedtls_chachapoly_update_aad( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
+                                               ad, ad_len ) );
     }
 #endif
 
@@ -357,7 +357,7 @@
     CIPHER_VALIDATE_RET( output != NULL );
     CIPHER_VALIDATE_RET( olen != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     *olen = 0;
     block_size = mbedtls_cipher_get_block_size( ctx );
@@ -382,8 +382,8 @@
     if( ctx->cipher_info->mode == MBEDTLS_MODE_GCM )
     {
         *olen = ilen;
-        return mbedtls_gcm_update( (mbedtls_gcm_context *) ctx->cipher_ctx, ilen, input,
-                           output );
+        return( mbedtls_gcm_update( (mbedtls_gcm_context *) ctx->cipher_ctx, ilen, input,
+                                    output ) );
     }
 #endif
 
@@ -391,14 +391,14 @@
     if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20_POLY1305 )
     {
         *olen = ilen;
-        return mbedtls_chachapoly_update( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
-                                                      ilen, input, output );
+        return( mbedtls_chachapoly_update( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
+                                           ilen, input, output ) );
     }
 #endif
 
     if ( 0 == block_size )
     {
-        return MBEDTLS_ERR_CIPHER_INVALID_CONTEXT;
+        return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT );
     }
 
     if( input == output &&
@@ -461,7 +461,7 @@
         {
             if( 0 == block_size )
             {
-                return MBEDTLS_ERR_CIPHER_INVALID_CONTEXT;
+                return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT );
             }
 
             /* Encryption: only cache partial blocks
@@ -766,7 +766,7 @@
     CIPHER_VALIDATE_RET( output != NULL );
     CIPHER_VALIDATE_RET( olen != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     *olen = 0;
 
@@ -835,8 +835,8 @@
 
         /* Set output size for decryption */
         if( MBEDTLS_DECRYPT == ctx->operation )
-            return ctx->get_padding( output, mbedtls_cipher_get_block_size( ctx ),
-                                     olen );
+            return( ctx->get_padding( output, mbedtls_cipher_get_block_size( ctx ),
+                                      olen ) );
 
         /* Set output size for encryption */
         *olen = mbedtls_cipher_get_block_size( ctx );
@@ -854,10 +854,8 @@
                                      mbedtls_cipher_padding_t mode )
 {
     CIPHER_VALIDATE_RET( ctx != NULL );
-    if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
 
-    if( MBEDTLS_MODE_CBC != ctx->cipher_info->mode )
+    if( NULL == ctx->cipher_info || MBEDTLS_MODE_CBC != ctx->cipher_info->mode )
     {
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
     }
@@ -908,14 +906,15 @@
     CIPHER_VALIDATE_RET( ctx != NULL );
     CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     if( MBEDTLS_ENCRYPT != ctx->operation )
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
 #if defined(MBEDTLS_GCM_C)
     if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
-        return mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx, tag, tag_len );
+        return( mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx,
+                                    tag, tag_len ) );
 #endif
 
 #if defined(MBEDTLS_CHACHAPOLY_C)
@@ -925,8 +924,8 @@
         if ( tag_len != 16U )
             return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
-        return mbedtls_chachapoly_finish( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
-                                                      tag );
+        return( mbedtls_chachapoly_finish( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
+                                           tag ) );
     }
 #endif
 
@@ -942,7 +941,7 @@
     CIPHER_VALIDATE_RET( ctx != NULL );
     CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     if( MBEDTLS_DECRYPT != ctx->operation )
     {
@@ -1012,7 +1011,7 @@
     CIPHER_VALIDATE_RET( output != NULL );
     CIPHER_VALIDATE_RET( olen != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     if( ( ret = mbedtls_cipher_set_iv( ctx, iv, iv_len ) ) != 0 )
         return( ret );
@@ -1050,7 +1049,7 @@
     CIPHER_VALIDATE_RET( olen != NULL );
     CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
 #if defined(MBEDTLS_GCM_C)
     if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
@@ -1107,7 +1106,7 @@
     CIPHER_VALIDATE_RET( olen != NULL );
     CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL );
     if( ctx->cipher_info == NULL )
-        return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
+        return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
 #if defined(MBEDTLS_GCM_C)
     if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )