From 13352a4ca7389bb226d6752c7bff6845d55dd4a7 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Thu, 26 Sep 2019 13:22:55 +1000
Subject: [PATCH] AP_ADSB: move is_valid_octal to is_valid_callsign and add
 tests for it

---
 libraries/AP_ADSB/AP_ADSB.cpp                 | 19 +++++++-
 libraries/AP_ADSB/AP_ADSB.h                   |  2 +
 .../AP_ADSB/tests/test_adsb_callsign.cpp      | 43 +++++++++++++++++++
 libraries/AP_ADSB/tests/wscript               |  7 +++
 4 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 libraries/AP_ADSB/tests/test_adsb_callsign.cpp
 create mode 100644 libraries/AP_ADSB/tests/wscript

diff --git a/libraries/AP_ADSB/AP_ADSB.cpp b/libraries/AP_ADSB/AP_ADSB.cpp
index 507d49f8eb..b815aefb9a 100644
--- a/libraries/AP_ADSB/AP_ADSB.cpp
+++ b/libraries/AP_ADSB/AP_ADSB.cpp
@@ -200,6 +200,23 @@ void AP_ADSB::deinit(void)
     }
 }
 
+bool AP_ADSB::is_valid_callsign(uint16_t octal)
+{
+    // treat "octal" as decimal and test if any decimal digit is > 7
+    if (octal > 7777) {
+        return false;
+    }
+
+    while (octal != 0) {
+        if (octal % 10 > 7) {
+            return false;
+        }
+        octal /= 10;
+    }
+
+    return true;
+}
+
 /*
  * periodic update to handle vehicle timeouts and trigger collision detection
  */
@@ -252,7 +269,7 @@ void AP_ADSB::update(void)
 
     if (out_state.cfg.squawk_octal_param != out_state.cfg.squawk_octal) {
         // param changed, check that it's a valid octal
-        if (!is_valid_octal(out_state.cfg.squawk_octal_param)) {
+        if (!is_valid_callsign(out_state.cfg.squawk_octal_param)) {
             // invalid, reset it to default
             out_state.cfg.squawk_octal_param = ADSB_SQUAWK_OCTAL_DEFAULT;
         }
diff --git a/libraries/AP_ADSB/AP_ADSB.h b/libraries/AP_ADSB/AP_ADSB.h
index 891191c521..17fcc9d5e3 100644
--- a/libraries/AP_ADSB/AP_ADSB.h
+++ b/libraries/AP_ADSB/AP_ADSB.h
@@ -85,6 +85,8 @@ public:
     void set_special_ICAO_target(const uint32_t new_icao_target) { _special_ICAO_target = (int32_t)new_icao_target; };
     bool is_special_vehicle(uint32_t icao) const { return _special_ICAO_target != 0 && (_special_ICAO_target == (int32_t)icao); }
 
+    // confirm a value is a valid callsign
+    static bool is_valid_callsign(uint16_t octal) WARN_IF_UNUSED;
 
 private:
     // initialize _vehicle_list
diff --git a/libraries/AP_ADSB/tests/test_adsb_callsign.cpp b/libraries/AP_ADSB/tests/test_adsb_callsign.cpp
new file mode 100644
index 0000000000..cdae65ec31
--- /dev/null
+++ b/libraries/AP_ADSB/tests/test_adsb_callsign.cpp
@@ -0,0 +1,43 @@
+#include <AP_gtest.h>
+
+#include <AP_ADSB/AP_ADSB.h>
+
+const AP_HAL::HAL& hal = AP_HAL::get_HAL();
+
+TEST(IsValidCallsign, Valid)
+{
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(7777));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(777));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(77));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(7));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(0));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(1111));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(111));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(11));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(1));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(0));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(7654));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(321));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(23));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(5));
+    EXPECT_TRUE(AP_ADSB::is_valid_callsign(5));
+}
+
+TEST(IsValidCallsign, Invalid)
+{
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(17777));
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(8888));
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(888));
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(88));
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(8));
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(9));
+
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(7778));
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(7788));
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(7888));
+    EXPECT_FALSE(AP_ADSB::is_valid_callsign(8888));
+}
+
+AP_GTEST_MAIN()
+
+#pragma GCC diagnostic pop
diff --git a/libraries/AP_ADSB/tests/wscript b/libraries/AP_ADSB/tests/wscript
new file mode 100644
index 0000000000..cd3e5e3ce7
--- /dev/null
+++ b/libraries/AP_ADSB/tests/wscript
@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+# encoding: utf-8
+
+def build(bld):
+    bld.ap_find_tests(
+        use='ap',
+    )