diff --git a/tools/analyse.cpp b/tools/analyse.cpp
index e38ae2d..67fbbf2 100644
--- a/tools/analyse.cpp
+++ b/tools/analyse.cpp
@@ -80,7 +80,73 @@ int main (int argc, char const **argv)
     };
 
     cruft::mapped_file data (argv[ARGS_INPUT]);
+    std::cout << "size: " << data.size () << '\n';
+
+    std::cout << "processing\n";
     emory::chunk::map src (data, p);
 
+    std::cout << "validating\n";
     std::cout << src.size () << " chunks\n";
+    std::sort (
+        src.elements.begin (),
+        src.elements.end   (),
+        [] (auto const &a, auto const &b) { return a.offset.first < b.offset.first; }
+    );
+    for (int i = 0, cursor = 0; i < std::ssize (src.elements); ++i) {
+        if (src.elements[i].offset.first != cursor) {
+            std::cout << "non-overlapping chunks\n";
+            return -1;
+        }
+        cursor = src.elements[i].offset.second;
+    }
+
+    if (src.elements.back ().offset.second != std::ssize (data)) {
+        std::cout << "invalid total size\n";
+        return -1;
+    }
+
+    std::sort (
+        src.elements.begin (),
+        src.elements.end (),
+        region_less
+    );
+
+    std::vector<off64_t> sizes;
+    std::transform (
+        src.elements.begin (),
+        src.elements.end   (),
+        std::back_inserter (sizes),
+        [] (auto const &val) { return val.size (); }
+    );
+    auto const myaccum = std::accumulate (std::begin (sizes), std::end (sizes), 0);
+    std::cout << myaccum << '\n';
+
+    auto const total_bytes = std::accumulate (
+        src.elements.begin (),
+        src.elements.end   (),
+        0,
+        [] (auto const accum, auto const rhs)
+    {
+        return accum + rhs.size ();
+    });
+
+
+    std::vector<emory::chunk::region> unique;
+    std::unique_copy (
+        src.elements.begin (),
+        src.elements.end   (),
+        std::back_inserter (unique),
+        region_equal
+    );
+    auto const unique_bytes = std::accumulate (
+        unique.begin (),
+        unique.end   (),
+        0, [] (auto const accum, auto const rhs) { return accum + rhs.size (); }
+    );
+
+    auto const duplicated_bytes = total_bytes - unique_bytes;
+    float const duplicated_fraction = float (duplicated_bytes) / total_bytes;
+
+    std::cout << duplicated_bytes << " duplicated bytes  of " << total_bytes << " (" << duplicated_fraction << "%)\n";
+    std::cout << (src.elements.size () - unique.size ()) << " duplicates\n";
 }