Move zigzag encoding function to new common/encoding.c file, add tests

src/test/unit/encoding_unittest.cc

@@ -0,0 +1,84 @@
+/*
+ * This file is part of Cleanflight.
+ *
+ * Cleanflight 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 of the License, or
+ * (at your option) any later version.
+ *
+ * Cleanflight 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 Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdint.h>
+
+extern "C" {
+    #include "common/encoding.h"
+}
+
+#include "unittest_macros.h"
+#include "gtest/gtest.h"
+
+typedef struct zigzagEncodingExpectation_t {
+    int32_t input;
+    uint32_t expected;
+} zigzagEncodingExpectation_t;
+
+typedef struct floatToIntEncodingExpectation_t {
+    float input;
+    uint32_t expected;
+} floatToIntEncodingExpectation_t;
+
+TEST(EncodingTest, ZigzagEncodingTest)
+{
+    // given
+    zigzagEncodingExpectation_t expectations[] = {
+        { 0, 0},
+        {-1, 1},
+        { 1, 2},
+        {-2, 3},
+        { 2, 4},
+
+        { 2147483646, 4294967292},
+        {-2147483647, 4294967293},
+        { 2147483647, 4294967294},
+        {-2147483648, 4294967295},
+    };
+    int expectationCount = sizeof(expectations) / sizeof(expectations[0]);
+
+    // expect
+
+    for (int i = 0; i < expectationCount; i++) {
+        zigzagEncodingExpectation_t *expectation = &expectations[i];
+
+        EXPECT_EQ(expectation->expected, zigzagEncode(expectation->input));
+    }
+}
+
+TEST(EncodingTest, FloatToIntEncodingTest)
+{
+    // given
+    floatToIntEncodingExpectation_t expectations[] = {
+        {0.0, 0x00000000},
+        {2.0, 0x40000000}, // Exponent should be in the top bits
+        {4.5, 0x40900000}
+    };
+    int expectationCount = sizeof(expectations) / sizeof(expectations[0]);
+
+    // expect
+
+    for (int i = 0; i < expectationCount; i++) {
+        floatToIntEncodingExpectation_t *expectation = &expectations[i];
+
+        EXPECT_EQ(expectation->expected, castFloatBytesToInt(expectation->input));
+    }
+}
+
+// STUBS
+
+extern "C" {
+}