From d8fa9aa322d00e796402cf99a35bdeae9b193c8b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Konstantin=20Ka=CC=88fer?= <mail@kkaefer.com>
Date: Tue, 13 May 2014 12:01:29 +0200
Subject: [PATCH] move weak_ptr list of tile_data objects to a map for faster
 lookups

---
 include/llmr/map/source.hpp |  3 ++-
 include/llmr/util/std.hpp   | 17 +++++++++++++++++
 src/map/source.cpp          | 16 +++++++---------
 3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/include/llmr/map/source.hpp b/include/llmr/map/source.hpp
index 7d47d61b7..da2d87ae8 100644
--- a/include/llmr/map/source.hpp
+++ b/include/llmr/map/source.hpp
@@ -12,6 +12,7 @@
 #include <vector>
 #include <string>
 #include <map>
+#include <set>
 
 namespace llmr {
 
@@ -69,7 +70,7 @@ private:
     const int32_t max_zoom;
 
     std::forward_list<Tile> tiles;
-    std::forward_list<std::weak_ptr<TileData>> tile_data;
+    std::map<Tile::ID, std::weak_ptr<TileData>> tile_data;
 };
 
 }
diff --git a/include/llmr/util/std.hpp b/include/llmr/util/std.hpp
index 4ef28d5f8..c09aa5ff6 100644
--- a/include/llmr/util/std.hpp
+++ b/include/llmr/util/std.hpp
@@ -11,6 +11,23 @@ template<typename T, typename ...Args>
     return ::std::unique_ptr<T>(new T(::std::forward<Args>(args)...));
 }
 
+
+template <typename Container, typename ForwardIterator, typename Predicate>
+void erase_if(Container &container, ForwardIterator it, const ForwardIterator end, Predicate pred) {
+    while (it != end) {
+        if (pred(*it)) {
+            container.erase(it++);
+        } else {
+            ++it;
+        }
+    }
+}
+
+template <typename Container, typename Predicate>
+void erase_if(Container &container, Predicate pred) {
+    erase_if(container, container.begin(), container.end(), pred);
+}
+
 }
 
 #endif
diff --git a/src/map/source.cpp b/src/map/source.cpp
index 384cb0a62..5571f74c7 100644
--- a/src/map/source.cpp
+++ b/src/map/source.cpp
@@ -7,6 +7,7 @@
 #include <llmr/util/string.hpp>
 #include <llmr/util/texturepool.hpp>
 #include <llmr/util/vec.hpp>
+#include <llmr/util/std.hpp>
 #include <llmr/geometry/glyph_atlas.hpp>
 
 
@@ -110,13 +111,10 @@ TileData::State Source::addTile(const Tile::ID& id) {
     // Try to find the associated TileData object.
     const Tile::ID normalized_id = id.normalized();
 
-    auto it = std::find_if(tile_data.begin(), tile_data.end(), [normalized_id](const std::weak_ptr<TileData>& tile_data) {
-        return !tile_data.expired() && tile_data.lock()->id == normalized_id;
-    });
-
+    auto it = tile_data.find(normalized_id);
     if (it != tile_data.end()) {
         // Create a shared_ptr handle. Note that this might be empty!
-        new_tile.data = it->lock();
+        new_tile.data = it->second.lock();
     }
 
     if (new_tile.data && new_tile.data->state == TileData::State::obsolete) {
@@ -138,7 +136,7 @@ TileData::State Source::addTile(const Tile::ID& id) {
         }
 
         new_tile.data->request();
-        tile_data.push_front(new_tile.data);
+        tile_data.emplace(new_tile.data->id, new_tile.data);
     }
 
     return new_tile.data->state;
@@ -269,9 +267,9 @@ bool Source::updateTiles() {
         return a.id.z < b.id.z;
     });
 
-    // Remove all the expired pointers from the list.
-    tile_data.remove_if([&retain_data](const std::weak_ptr<TileData>& tile_data) {
-        const std::shared_ptr<TileData> tile = tile_data.lock();
+    // Remove all the expired pointers from the set.
+    std::erase_if(tile_data, [&retain_data](const std::pair<Tile::ID, std::weak_ptr<TileData>>& pair) {
+        const std::shared_ptr<TileData> tile = pair.second.lock();
         if (!tile) {
             return true;
         }