examples: Make possible to select the finger to enroll/verify

Move some common functions to an utilities file.

examples/utilities.c

@@ -0,0 +1,94 @@
+/*
+ * Utilities for example programs
+ *
+ * Copyright (C) 2019 Marco Trevisan <marco.trevisan@canonical.com>
+ *
+ * This library 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 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <libfprint/fprint.h>
+#include <stdio.h>
+
+#include "utilities.h"
+
+const char *
+finger_to_string (FpFinger finger)
+{
+  switch (finger)
+    {
+    case FP_FINGER_LEFT_THUMB:
+      return "left thumb";
+
+    case FP_FINGER_LEFT_INDEX:
+      return "left index";
+
+    case FP_FINGER_LEFT_MIDDLE:
+      return "left middle";
+
+    case FP_FINGER_LEFT_RING:
+      return "left ring";
+
+    case FP_FINGER_LEFT_LITTLE:
+      return "left little";
+
+    case FP_FINGER_RIGHT_THUMB:
+      return "right thumb";
+
+    case FP_FINGER_RIGHT_INDEX:
+      return "right index";
+
+    case FP_FINGER_RIGHT_MIDDLE:
+      return "right middle";
+
+    case FP_FINGER_RIGHT_RING:
+      return "right ring";
+
+    case FP_FINGER_RIGHT_LITTLE:
+      return "right little";
+
+    default:
+      return "unknown";
+    }
+}
+
+FpFinger
+finger_chooser (void)
+{
+  int i;
+  const FpFinger all_fingers[] = {
+    FP_FINGER_LEFT_THUMB,
+    FP_FINGER_LEFT_INDEX,
+    FP_FINGER_LEFT_MIDDLE,
+    FP_FINGER_LEFT_RING,
+    FP_FINGER_LEFT_LITTLE,
+    FP_FINGER_RIGHT_THUMB,
+    FP_FINGER_RIGHT_INDEX,
+    FP_FINGER_RIGHT_MIDDLE,
+    FP_FINGER_RIGHT_RING,
+    FP_FINGER_RIGHT_LITTLE,
+  };
+
+  for (i = all_fingers[0]; i <= G_N_ELEMENTS (all_fingers); ++i)
+    g_print("  [%d] %s\n", (i - all_fingers[0]), finger_to_string (i));
+
+  g_print ("> ");
+  if (!scanf ("%d%*c", &i))
+    return FP_FINGER_UNKNOWN;
+
+  if (i < 0 || i >= G_N_ELEMENTS (all_fingers))
+    return FP_FINGER_UNKNOWN;
+
+  return all_fingers[i];
+}