First pass idLib conversion from hex rays4.

source/shared/idlib/math/mathlib.cpp

@@ -0,0 +1,31 @@
+#include "mathlib.h"
+
+#include <cstdint>
+
+int InterleaveBits(const int x, const int y) {
+    const std::uint32_t xBits = static_cast<std::uint32_t>(x);
+    const std::uint32_t yBits = static_cast<std::uint32_t>(y);
+    std::uint32_t interleaved = 0;
+
+    for (int bit = 0; bit < 16; ++bit) {
+        interleaved |= ((xBits >> bit) & 1u) << (bit * 2);
+        interleaved |= ((yBits >> bit) & 1u) << (bit * 2 + 1);
+    }
+
+    return static_cast<int>(interleaved);
+}
+
+void DeInterleaveBits(const int bits, int& x, int& y) {
+    const std::uint32_t interleaved = static_cast<std::uint32_t>(bits);
+    std::uint32_t xBits = 0;
+    std::uint32_t yBits = 0;
+
+    for (int bit = 0; bit < 16; ++bit) {
+        xBits |= ((interleaved >> (bit * 2)) & 1u) << bit;
+        yBits |= ((interleaved >> (bit * 2 + 1)) & 1u) << bit;
+    }
+
+    x = static_cast<int>(xBits);
+    y = static_cast<int>(yBits);
+}
+