1 files changed, 107 insertions, 0 deletions
diff --git a/src/openpgp/hash.h b/src/openpgp/hash.h
new file mode 100644
index 00000000..0952c602
--- /dev/null
+++ b/src/openpgp/hash.h
@@ -0,0 +1,107 @@
+// Copyright (c) 2020, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include <vector>
+
+#include <gcrypt.h>
+#include <span.h>
+
+namespace openpgp
+{
+
+class hash
+{
+public:
+  enum algorithm : uint8_t
+  {
+    sha256 = 8,
+  };
+
+  hash(const hash &) = delete;
+  hash &operator=(const hash &) = delete;
+
+  hash(uint8_t algorithm)
+    : algorithm(algorithm)
+    , consumed(0)
+  {
+    if (gcry_md_open(&md, algorithm, 0) != GPG_ERR_NO_ERROR)
+    {
+      throw std::runtime_error("failed to create message digest object");
+    }
+  }
+
+  ~hash()
+  {
+    gcry_md_close(md);
+  }
+
+  hash &operator<<(uint8_t byte)
+  {
+    gcry_md_putc(md, byte);
+    ++consumed;
+    return *this;
+  }
+
+  hash &operator<<(const epee::span<const uint8_t> &bytes)
+  {
+    gcry_md_write(md, &bytes[0], bytes.size());
+    consumed += bytes.size();
+    return *this;
+  }
+
+  hash &operator<<(const std::vector<uint8_t> &bytes)
+  {
+    return *this << epee::to_span(bytes);
+  }
+
+  std::vector<uint8_t> finish() const
+  {
+    std::vector<uint8_t> result(gcry_md_get_algo_dlen(algorithm));
+    const void *digest = gcry_md_read(md, algorithm);
+    if (digest == nullptr)
+    {
+      throw std::runtime_error("failed to read the digest");
+    }
+    memcpy(&result[0], digest, result.size());
+    return result;
+  }
+
+  size_t consumed_bytes() const
+  {
+    return consumed;
+  }
+
+private:
+  const uint8_t algorithm;
+  gcry_md_hd_t md;
+  size_t consumed;
+};
+
+}