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/aes/crypt_and_hash.c b/programs/aes/crypt_and_hash.c
index a5acf5b..8d671ab 100644
--- a/programs/aes/crypt_and_hash.c
+++ b/programs/aes/crypt_and_hash.c
@@ -100,7 +100,7 @@
unsigned char diff;
const mbedtls_cipher_info_t *cipher_info;
- const mbedtls_md_info_t *md_info;
+ mbedtls_md_handle_t md_info;
mbedtls_cipher_context_t cipher_ctx;
mbedtls_md_context_t md_ctx;
#if defined(_WIN32_WCE)
@@ -192,7 +192,7 @@
}
md_info = mbedtls_md_info_from_string( argv[5] );
- if( md_info == NULL )
+ if( md_info == MBEDTLS_MD_INVALID_HANDLE )
{
mbedtls_fprintf( stderr, "Message Digest '%s' not found\n", argv[5] );
goto exit;