From 9c3ddcbc183a9a96f10cdb14f28258ea61f5f7c5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=96zg=C3=BCr=20Kesim?= <oec-taler@kesim.org>
Date: Tue, 27 Jun 2023 18:57:05 +0200
Subject: added TALER_adult_age(struct TALER_AgeMask *mask)

---
 src/include/taler_util.h        |  8 ++++++++
 src/util/age_restriction.c      |  3 ++-
 src/util/test_age_restriction.c | 34 +++++++++++++++++++++++++++++++++-
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/src/include/taler_util.h b/src/include/taler_util.h
index dc30fca31..e0473bff7 100644
--- a/src/include/taler_util.h
+++ b/src/include/taler_util.h
@@ -622,6 +622,14 @@ TALER_get_lowest_age (
   const struct TALER_AgeMask *mask,
   uint8_t age);
 
+/* @brief Get the lowest age for the largest age group
+ *
+ * @param mask the age mask
+ * @return lowest age for the largest age group
+ */
+#define TALER_adult_age(mask) \
+  sizeof((mask)->bits) * 8 - __builtin_clz ((mask)->bits) - 1
+
 /**
  * Handle to an external process that will assist
  * with some JSON-to-JSON conversion.
diff --git a/src/util/age_restriction.c b/src/util/age_restriction.c
index 839ed7cd5..6f0702298 100644
--- a/src/util/age_restriction.c
+++ b/src/util/age_restriction.c
@@ -23,6 +23,7 @@
 #include "taler_signatures.h"
 #include <gnunet/gnunet_json_lib.h>
 #include <gcrypt.h>
+#include <stdint.h>
 
 struct
 #ifndef AGE_RESTRICTION_WITH_ECDSA
@@ -746,7 +747,7 @@ TALER_parse_coarse_date (
 
   /* calculate the limit date for the largest age group */
   localtime_r (&(time_t){time (NULL)}, &limit);
-  limit.tm_year -= TALER_get_lowest_age (mask, 255);
+  limit.tm_year -= TALER_adult_age (mask);
   GNUNET_assert (-1 != mktime (&limit));
 
   if ((limit.tm_year < date.tm_year)
diff --git a/src/util/test_age_restriction.c b/src/util/test_age_restriction.c
index 29e722acc..53cacc6d5 100644
--- a/src/util/test_age_restriction.c
+++ b/src/util/test_age_restriction.c
@@ -233,7 +233,7 @@ test_lowest (void)
     {.age = 22, .expected = 21 },
   };
 
-  for (uint8_t n = 0; n < 21; n++)
+  for (uint8_t n = 0; n < sizeof(test) / sizeof(test[0]); n++)
   {
     uint8_t l = TALER_get_lowest_age (&mask, test[n].age);
     printf ("lowest[%d] for age %d, expected lowest: %d, got: %d\n",
@@ -246,6 +246,36 @@ test_lowest (void)
 }
 
 
+enum GNUNET_GenericReturnValue
+test_adult (void)
+{
+  struct { struct TALER_AgeMask mask; uint8_t expected; }
+  test[] = {
+    { .mask = {.bits = 1 | 1 << 2},
+      .expected = 2 },
+    { .mask = {.bits = 1 | 1 << 2 | 1 << 3},
+      .expected = 3 },
+    { .mask = {.bits = 1 | 1 << 3},
+      .expected = 3 },
+    { .mask = {.bits = 1 | 1 << 22},
+      .expected = 22 },
+    { .mask = {.bits = 1 | 1 << 10 | 1 << 16 | 1 << 22},
+      .expected = 22 },
+  };
+  for (uint8_t n = 0; n < sizeof(test) / sizeof(test[0]); n++)
+  {
+    uint8_t l = TALER_adult_age (&test[n].mask);
+    printf ("adult[%d] for mask %s, expected: %d, got: %d\n",
+            n, TALER_age_mask_to_string (&test[n].mask), test[n].expected, l);
+    if (test[n].expected != l)
+      return GNUNET_SYSERR;
+  }
+  printf ("done with adult\n");
+
+  return GNUNET_OK;
+}
+
+
 static struct TALER_AgeMask age_mask = {
   .bits = 1 | 1 << 8 | 1 << 10 | 1 << 12 | 1 << 14 | 1 << 16 | 1 << 18 | 1 << 21
 };
@@ -381,6 +411,8 @@ main (int argc,
   }
   if (GNUNET_OK != test_dates ())
     return 4;
+  if (GNUNET_OK != test_adult ())
+    return 5;
   return 0;
 }
 
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