From c2de3672e5b50aba198c2cf22c0ac08f6bf2618f Mon Sep 17 00:00:00 2001
From: Cory Slep <coryslep1@mac.com>
Date: Sat, 14 Sep 2019 13:39:40 +0200
Subject: [PATCH] Add IsSupportedDigestAlgorithm

---
 digest.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/digest.go b/digest.go
index 9aaeb8c..b5c6242 100644
--- a/digest.go
+++ b/digest.go
@@ -22,6 +22,14 @@ var digestToDef = map[DigestAlgorithm]crypto.Hash{
 	DigestSha512: crypto.SHA512,
 }
 
+// IsSupportedDigestAlgorithm returns true if hte string is supported by this
+// library, is not a hash known to be weak, and is supported by the hardware.
+func IsSupportedDigestAlgorithm(algo string) bool {
+	uc := DigestAlgorithm(strings.ToUpper(algo))
+	c, ok := digestToDef[uc]
+	return ok && c.Available()
+}
+
 func getHash(alg DigestAlgorithm) (h hash.Hash, toUse DigestAlgorithm, err error) {
 	upper := DigestAlgorithm(strings.ToUpper(string(alg)))
 	c, ok := digestToDef[upper]