refactor

repertory/librepertory/include/file_manager/ring_file_base.hpp

@@ -69,6 +69,8 @@ private:
 
   void reader_thread();
 
+  void update_position(std::size_t count, bool is_forward);
+
 protected:
   [[nodiscard]] auto get_read_state_size() const -> std::size_t;
 

repertory/librepertory/src/file_manager/ring_file_base.cpp

@@ -183,32 +183,7 @@ auto ring_file_base::download_chunk(std::size_t chunk,
 }
 
 void ring_file_base::forward(std::size_t count) {
-  mutex_lock chunk_lock(chunk_mtx_);
+  update_position(count, true);
-  if ((ring_pos_ + count) > (total_chunks_ - 1U)) {
-    count = (total_chunks_ - 1U) - ring_pos_;
-  }
-
-  if ((ring_pos_ + count) <= ring_end_) {
-    ring_pos_ += count;
-  } else {
-    auto added = count - (ring_end_ - ring_pos_);
-    if (added >= ring_state_.size()) {
-      ring_state_.set(0U, ring_state_.size(), false);
-      ring_pos_ += count;
-      ring_begin_ += added;
-    } else {
-      for (std::size_t idx = 0U; idx < added; ++idx) {
-        ring_state_[(ring_begin_ + idx) % ring_state_.size()] = false;
-      }
-      ring_begin_ += added;
-      ring_pos_ += count;
-    }
-
-    ring_end_ =
-        std::min(total_chunks_ - 1U, ring_begin_ + ring_state_.size() - 1U);
-  }
-
-  chunk_notify_.notify_all();
 }
 
 auto ring_file_base::get_read_state() const -> boost::dynamic_bitset<> {
@@ -347,30 +322,7 @@ void ring_file_base::reader_thread() {
 }
 
 void ring_file_base::reverse(std::size_t count) {
-  mutex_lock chunk_lock(chunk_mtx_);
+  update_position(count, false);
-  count = std::min(ring_pos_, count);
-
-  if ((ring_pos_ - count) >= ring_begin_) {
-    ring_pos_ -= count;
-  } else {
-    auto removed = count - (ring_pos_ - ring_begin_);
-    if (removed >= ring_state_.size()) {
-      ring_state_.set(0U, ring_state_.size(), false);
-      ring_pos_ -= count;
-      ring_begin_ = ring_pos_;
-    } else {
-      for (std::size_t idx = 0U; idx < removed; ++idx) {
-        ring_state_[(ring_end_ - idx) % ring_state_.size()] = false;
-      }
-      ring_begin_ -= removed;
-      ring_pos_ -= count;
-    }
-
-    ring_end_ =
-        std::min(total_chunks_ - 1U, ring_begin_ + ring_state_.size() - 1U);
-  }
-
-  chunk_notify_.notify_all();
 }
 
 void ring_file_base::set(std::size_t first_chunk, std::size_t current_chunk) {
@@ -401,4 +353,46 @@ void ring_file_base::set_api_path(const std::string &api_path) {
   open_file_base::set_api_path(api_path);
   chunk_notify_.notify_all();
 }
+
+void ring_file_base::update_position(std::size_t count, bool is_forward) {
+  mutex_lock chunk_lock(chunk_mtx_);
+
+  if (is_forward) {
+    if ((ring_pos_ + count) > (total_chunks_ - 1U)) {
+      count = (total_chunks_ - 1U) - ring_pos_;
+    }
+  } else {
+    count = std::min(ring_pos_, count);
+  }
+
+  if (is_forward ? (ring_pos_ + count) <= ring_end_
+                 : (ring_pos_ - count) >= ring_begin_) {
+    ring_pos_ += is_forward ? count : -count;
+  } else {
+    auto delta = is_forward ? count - (ring_end_ - ring_pos_)
+                            : count - (ring_pos_ - ring_begin_);
+
+    if (delta >= ring_state_.size()) {
+      ring_state_.set(0U, ring_state_.size(), false);
+      ring_pos_ += is_forward ? count : -count;
+      ring_begin_ += is_forward ? delta : -delta;
+    } else {
+      for (std::size_t idx = 0U; idx < delta; ++idx) {
+        if (is_forward) {
+          ring_state_[(ring_begin_ + idx) % ring_state_.size()] = false;
+        } else {
+          ring_state_[(ring_end_ - idx) % ring_state_.size()] = false;
+        }
+      }
+
+      ring_begin_ += is_forward ? delta : -delta;
+      ring_pos_ += is_forward ? count : -count;
+    }
+
+    ring_end_ =
+        std::min(total_chunks_ - 1U, ring_begin_ + ring_state_.size() - 1U);
+  }
+
+  chunk_notify_.notify_all();
+}
 } // namespace repertory