Add generic wrappers for performing message digest operations.

src/platform/vboot_reference/tests/signature_digest.c

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Utility that outputs the message digest of the contents of a file in a
  * format that can be used as input to OpenSSL for an RSA signature.
  * Needed until the stable OpenSSL release supports SHA-256/512 digests for
  * RSA signatures.
  * Outputs DigestInfo || Digest where DigestInfo is the OID depending on the
  * choice of the hash algorithm (see padding.c).
  *
  */
 
 #include "signature_digest.h"
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 
-#include "digest_utility.h"
 #include "padding.h"
 #include "sha.h"
+#include "sha_utility.h"
 
 uint8_t* prepend_digestinfo(int algorithm, uint8_t* digest) {
   const int digest_size = hash_size_map[algorithm];
   const int digestinfo_size = digestinfo_size_map[algorithm];
   const uint8_t* digestinfo = hash_digestinfo_map[algorithm];
   uint8_t* p = malloc(digestinfo_size + digest_size);
   memcpy(p, digestinfo, digestinfo_size);
   memcpy(p + digestinfo_size, digest, digest_size);
   return p;
 }
@@ skipping 12 matching lines @@
       fprintf(stderr, "\t%d for %s\n", i, algo_strings[i]);
     return -1;
   }
 
   algorithm = atoi(argv[1]);
   if (algorithm >= kNumAlgorithms) {
     fprintf(stderr, "Invalid Algorithm!\n");
     goto failure;
   }
 
-  if (!(digest = calculate_digest(argv[2], algorithm)))
+  if (!(digest = DigestFile(argv[2], algorithm)))
     goto failure;
 
   info_digest = prepend_digestinfo(algorithm, digest);
   write(1, info_digest, hash_size_map[algorithm] +
         digestinfo_size_map[algorithm]);
 
 failure:
   free(digest);
   free(info_digest);
   free(signature);
 
   return 0;
 }