Initial import of libdpf.

Co-authored-by: Cursor <cursoragent@cursor.com>

test/tests/setbit_index_iterable_test.cpp

@@ -0,0 +1,37 @@
+#include <gtest/gtest.h>
+
+#include "dpf.hpp"
+
+TEST(SetbitIndexIterableTest, BasicUsage)
+{
+    using input_type = uint16_t;
+    using output_type = dpf::bit;
+    input_type x = 0xAAAA;
+    output_type y = dpf::bit::one;
+    auto [dpf0, dpf1] = dpf::make_dpf(x, y);
+    auto [buf0, iter0] = dpf::eval_full(dpf0);
+    auto [buf1, iter1] = dpf::eval_full(dpf1);
+
+    auto setbit0 = dpf::indices_set_in(iter0),
+         setbit1 = dpf::indices_set_in(iter1);
+
+    auto it0 = std::begin(setbit0), it0end = std::end(setbit0),
+         it1 = std::begin(setbit1), it1end = std::end(setbit1);
+    for (; it0 != it0end && it1 != it1end; ++it0, ++it1)
+    {
+        if (*it0 == x)
+        {
+            ASSERT_EQ(*(++it0), *it1);
+        }
+        else if (*it1 == x)
+        {
+            ASSERT_EQ(*it0, *(++it1));
+        }
+        else
+        {
+            ASSERT_EQ(*it0, *it1);
+        }
+    }
+    ASSERT_EQ(it0, it0end);
+    ASSERT_EQ(it1, it1end);
+}