From 88adf3f7f2e9c6f1ea3c722ead41a5579b3292bf Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sat, 5 Oct 2019 08:30:00 +0200
Subject: Add sha{1,256}::empty()

---
 libbutl/sha256.cxx | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

(limited to 'libbutl/sha256.cxx')

diff --git a/libbutl/sha256.cxx b/libbutl/sha256.cxx
index 6dbe2a0..31730a2 100644
--- a/libbutl/sha256.cxx
+++ b/libbutl/sha256.cxx
@@ -67,7 +67,7 @@ namespace butl
 {
   sha256::
   sha256 ()
-      : done_ (false)
+      : done_ (false), empty_ (true)
   {
     SHA256_Init (reinterpret_cast<SHA256_CTX*> (buf_));
   }
@@ -75,7 +75,13 @@ namespace butl
   void sha256::
   append (const void* b, size_t n)
   {
-    SHA256_Update (reinterpret_cast<SHA256_CTX*> (buf_), b, n);
+    if (n != 0)
+    {
+      SHA256_Update (reinterpret_cast<SHA256_CTX*> (buf_), b, n);
+
+      if (empty_)
+        empty_ = false;
+    }
   }
 
   void sha256::
-- 
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