1 files changed, 49 insertions, 0 deletions
diff --git a/src/exchangedb/pg_compute_shard.c b/src/exchangedb/pg_compute_shard.c
new file mode 100644
index 000000000..1dea591f1
--- /dev/null
+++ b/src/exchangedb/pg_compute_shard.c
@@ -0,0 +1,49 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2022 Taler Systems SA
+
+   TALER is free software; you can redistribute it and/or modify it under the
+   terms of the GNU General Public License as published by the Free Software
+   Foundation; either version 3, or (at your option) any later version.
+
+   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along with
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file exchangedb/pg_compute_shard.c
+ * @brief Implementation of the compute_shard function for Postgres
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "taler_error_codes.h"
+#include "taler_dbevents.h"
+#include "taler_pq_lib.h"
+#include "pg_compute_shard.h"
+#include "pg_helper.h"
+
+
+uint64_t
+TEH_PG_compute_shard (const struct TALER_MerchantPublicKeyP *merchant_pub)
+{
+  uint32_t res;
+
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CRYPTO_kdf (&res,
+                                    sizeof (res),
+                                    merchant_pub,
+                                    sizeof (*merchant_pub),
+                                    "VOID",
+                                    4,
+                                    NULL, 0));
+  /* interpret hash result as NBO for platform independence,
+     convert to HBO and map to [0..2^31-1] range */
+  res = ntohl (res);
+  if (res > INT32_MAX)
+    res += INT32_MIN;
+  GNUNET_assert (res <= INT32_MAX);
+  return (uint64_t) res;
+}