From b5e93c15fb1c1188f6b2bf94fe2ef98ba34e6574 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Tue, 29 Dec 2020 08:37:32 +1000
Subject: [PATCH] analyse: avoid copying the chunk data for duplicate detection

---
 tools/analyse.cpp | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/tools/analyse.cpp b/tools/analyse.cpp
index effce36..7ddfdfa 100644
--- a/tools/analyse.cpp
+++ b/tools/analyse.cpp
@@ -220,18 +220,22 @@ int main (int argc, char const **argv)
         return accum + rhs.size ();
     });
 
+    // WARNING: this is destructive, but suits our purposes for the moment as
+    // we intend to remove the reliance on in memory storage as much as we can.
+    auto const init_size = src.size ();
+    src.erase(
+        std::unique (
+            src.begin (),
+            src.end   (),
+            region_equal
+        ),
+        src.end ()
+    );
 
-    std::vector<emory::chunk::region> unique;
-    std::unique_copy (
+    auto const unique_bytes = std::accumulate (
         src.begin (),
         src.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 (); }
+        0, [] (auto const &accum, auto const &rhs) { return accum + rhs.size (); }
     );
 
     auto const duplicated_bytes = total_bytes - unique_bytes;
@@ -244,5 +248,5 @@ int main (int argc, char const **argv)
         100.f * duplicated_fraction
     );
 
-    fmt::print ("{} duplicates\n", src.size () - unique.size ());
+    fmt::print ("{} duplicates\n", init_size - src.size ());
 }