clamp: Add.

clamp.h

@@ -0,0 +1,50 @@
+/*!
+ * \file
+ */
+/*
+ * zlib License
+ *
+ * Copyright (C) 2020 KOBAYASHI Daisuke
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+#ifndef CLAMP_H_
+#define CLAMP_H_
+
+#ifndef CLAMP_T
+#define CLAMP_T int
+#endif
+
+#define CLAMP_MIN(a, b) (((a) < (b)) ? (a) : (b))
+#define CLAMP_MAX(a, b) (((a) > (b)) ? (a) : (b))
+
+/** Clamps a variable to a given range.
+ *
+ * @param value value to clamp
+ * @param min lower limit
+ * @param max upper limit
+ */
+static inline CLAMP_T clamp(CLAMP_T value, CLAMP_T min, CLAMP_T max)
+{
+    return CLAMP_MIN(CLAMP_MAX(value, min), max);
+}
+
+#undef CLAMP_MIN
+#undef CLAMP_MAX
+
+#endif /* CLAMP_H_ */

test/clamp_test.cpp

@@ -0,0 +1,51 @@
+/*
+ * zlib License
+ *
+ * Copyright (C) 2029 KOBAYASHI Daisuke
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+#include <gtest/gtest.h>
+
+extern "C" {
+#include "clamp.h"
+}
+
+TEST(Clamp, Lower)
+{
+    EXPECT_EQ(-10, clamp(-20, -10, 10));
+    EXPECT_EQ(0, clamp(-10, 0, 10));
+    EXPECT_EQ(200, clamp(100, 200, 300));
+}
+
+TEST(Clamp, Value)
+{
+    EXPECT_EQ(-300, clamp(-300, -500, 100));
+    EXPECT_EQ(0, clamp(0, 0, 10));
+    EXPECT_EQ(1, clamp(1, 0, 10));
+    EXPECT_EQ(5, clamp(5, 0, 10));
+    EXPECT_EQ(10, clamp(10, 0, 10));
+    EXPECT_EQ(50, clamp(50, 0, 500));
+    EXPECT_EQ(1001, clamp(1001, 1000, 10000));
+}
+TEST(Clamp, Upper)
+{
+    EXPECT_EQ(-20, clamp(10, -300, -20));
+    EXPECT_EQ(10, clamp(11, 0, 10));
+    EXPECT_EQ(1000, clamp(2000, 0, 1000));
+}