1 files changed, 57 insertions, 0 deletions

diff --git a/src/reducer/validation_CH_AHV.c b/src/reducer/validation_CH_AHV.c
new file mode 100644
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--- /dev/null
+++ b/src/reducer/validation_CH_AHV.c
@@ -0,0 +1,57 @@
+/*
+  This file is part of Anastasis
+  Copyright (C) 2020, 2021 Taler Systems SA
+
+  Anastasis is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Lesser General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  Anastasis 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
+  Anastasis; see the file COPYING.GPL.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file redux/validation_CH_AHV.c
+ * @brief anastasis reducer api
+ * @author Christian Grothoff
+ * @author Dominik Meister
+ * @author Dennis Neufeld
+ */
+#include <string.h>
+#include <stdbool.h>
+
+/**
+ * Function to validate a Swiss AHV number.
+ *
+ * @param avh_number ahv number to validate (input)
+ * @return true if validation passed, else false
+ */
+bool
+CH_AHV_check (const char *ahv_number)
+{
+  unsigned int checknum;
+  unsigned int next_ten;
+  const char *pos = &ahv_number[strlen (ahv_number) - 1];
+  bool phase = true;
+  unsigned int calculation = 0;
+
+  checknum = *pos - 48;
+  while (pos > ahv_number)
+  {
+    pos--;
+    if ('.' == *pos)
+      continue;
+    if (phase)
+      calculation += ((*pos - 48) * 3);
+    else
+      calculation += *pos - 48;
+    phase = ! phase;
+  }
+  /* round up to the next ten */
+  next_ten = ((calculation + 9) / 10) * 10;
+  calculation = next_ten - calculation;
+  return (checknum == calculation);
+}