Introduce MD handle type
As has been previously done for ciphersuites, this commit introduces
a zero-cost abstraction layer around the type
mbedtls_md_info const *
whose valid values represent implementations of message digest algorithms.
Access to a particular digest implementation can be requested by name or
digest ID through the API mbedtls_md_info_from_xxx(), which either returns
a valid implementation or NULL, representing failure.
This commit replaces such uses of `mbedtls_md_info const *` by an abstract
type `mbedtls_md_handle_t` whose valid values represent digest implementations,
and which has a designated invalid value MBEDTLS_MD_INVALID_HANDLE.
The purpose of this abstraction layer is to pave the way for builds which
support precisely one digest algorithm. In this case, mbedtls_md_handle_t
can be implemented as a two-valued type, with one value representing the
invalid handle, and the unique valid value representing the unique enabled
digest.
diff --git a/programs/hash/generic_sum.c b/programs/hash/generic_sum.c
index 709a149..ed5357f 100644
--- a/programs/hash/generic_sum.c
+++ b/programs/hash/generic_sum.c
@@ -53,7 +53,7 @@
#else
-static int generic_wrapper( const mbedtls_md_info_t *md_info, char *filename, unsigned char *sum )
+static int generic_wrapper( mbedtls_md_handle_t md_info, char *filename, unsigned char *sum )
{
int ret = mbedtls_md_file( md_info, filename, sum );
@@ -66,7 +66,7 @@
return( ret );
}
-static int generic_print( const mbedtls_md_info_t *md_info, char *filename )
+static int generic_print( mbedtls_md_handle_t md_info, char *filename )
{
int i;
unsigned char sum[MBEDTLS_MD_MAX_SIZE];
@@ -81,7 +81,7 @@
return( 0 );
}
-static int generic_check( const mbedtls_md_info_t *md_info, char *filename )
+static int generic_check( mbedtls_md_handle_t md_info, char *filename )
{
int i;
size_t n;
@@ -177,7 +177,7 @@
{
int ret = 1, i;
int exit_code = MBEDTLS_EXIT_FAILURE;
- const mbedtls_md_info_t *md_info;
+ mbedtls_md_handle_t md_info;
mbedtls_md_context_t md_ctx;
mbedtls_md_init( &md_ctx );
@@ -210,7 +210,7 @@
* Read the MD from the command line
*/
md_info = mbedtls_md_info_from_string( argv[1] );
- if( md_info == NULL )
+ if( md_info == MBEDTLS_MD_INVALID_HANDLE )
{
mbedtls_fprintf( stderr, "Message Digest '%s' not found\n", argv[1] );
return( exit_code );