Annotate noexcept and constexpr with HEDLEY, and add interval containment, ChaCha, and the dyadic range tables.

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

examples/evaluation/buffered_prg.cpp

@@ -0,0 +1,62 @@
+#include <cstdint>
+#include <cstring>
+#include <iostream>
+
+#include "dpf.hpp"
+
+/// `buffered_prg` is a forward cursor, one stream per value type.
+/// `at<I>(index)` reads by absolute index and does not move the cursor.
+/// `lane_table` is the seekable form: value and mask streams per role.
+int main()
+{
+    //! [buffered-prg]
+    dpf::randomness::aes_buffered_prg<std::uint64_t, std::uint32_t> prg(
+        /*per stream*/ 64);
+
+    std::uint64_t first = prg.get<0>();
+    std::uint64_t second = prg.get<0>();
+    // Absolute index 0 is `first` again. The cursor stays at 2.
+    std::uint64_t replay = prg.at<0>(0);
+    std::uint32_t other_stream = prg.get<1>();
+
+    std::uint64_t batch[4];
+    prg.fill<0>(batch, 4);
+    //! [buffered-prg]
+
+    if (std::memcmp(&replay, &first, sizeof(first)) != 0)
+    {
+        std::cerr << "buffered_prg at(0)\n";
+        return 1;
+    }
+    if (prg.sampled<0>() != 6)
+    {
+        std::cerr << "buffered_prg cursor\n";
+        return 1;
+    }
+    // Stream 1 has its own cursor.
+    if (prg.sampled<1>() != 1)
+    {
+        std::cerr << "buffered_prg stream 1\n";
+        return 1;
+    }
+    (void)second;
+    (void)other_stream;
+    (void)batch;
+
+    //! [lane-table]
+    dpf::randomness::lane_table<std::uint64_t> lanes(/*window*/ 32);
+    // Order does not matter. Masks are a separate stream from values.
+    auto v_late = lanes.value_at(/*role*/ 3, /*index*/ 10);
+    auto v_early = lanes.value_at(3, 10);
+    auto mask = lanes.mask_at(3, 10);
+    //! [lane-table]
+    if (std::memcmp(&v_late, &v_early, sizeof(v_late)) != 0)
+    {
+        std::cerr << "lane_table replay\n";
+        return 1;
+    }
+    (void)mask;
+
+    std::cout << "ok\n";
+    return 0;
+}