latest SDK

foobar2000/helpers/playlist_position_reference_tracker.h

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+#pragma once
+
+class playlist_position_reference_tracker : public playlist_callback_impl_base {
+public:
+	//! @param p_trackitem Specifies whether we want to track some specific item rather than just an offset in a playlist. When set to true, item index becomes invalidated when the item we're tracking is removed.
+	playlist_position_reference_tracker(bool p_trackitem = true) : playlist_callback_impl_base(~0), m_trackitem(p_trackitem), m_playlist(pfc_infinite), m_item(pfc_infinite) {}
+	
+	void on_items_added(t_size p_playlist,t_size p_start, const pfc::list_base_const_t<metadb_handle_ptr> & p_data,const bit_array & p_selection) {
+		if (p_playlist == m_playlist && m_item != pfc_infinite && p_start <= m_item) {
+			m_item += p_data.get_count();
+		}
+	}
+	void on_items_reordered(t_size p_playlist,const t_size * p_order,t_size p_count) {
+		if (p_playlist == m_playlist) {
+			if (m_item < p_count) {
+				m_item = order_helper::g_find_reverse(p_order,m_item);
+			} else {
+				m_item = pfc_infinite;
+			}
+		}
+	}
+
+	void on_items_removed(t_size p_playlist,const bit_array & p_mask,t_size p_old_count,t_size p_new_count) {
+		if (p_playlist == m_playlist) {
+			if (m_item < p_old_count) {
+				const t_size item_before = m_item;
+				for(t_size walk = p_mask.find_first(true,0,p_old_count); walk < p_old_count; walk = p_mask.find_next(true,walk,p_old_count)) {
+					if (walk < item_before) { 
+						m_item--;
+					} else if (walk == item_before) {
+						if (m_trackitem) m_item = pfc_infinite;
+						break;
+					} else {
+						break;
+					}
+				}
+				if (m_item >= p_new_count) m_item = pfc_infinite;
+			} else {
+				m_item = pfc_infinite;
+			}
+		}
+	}
+
+	//todo? could be useful in some cases
+	void on_items_replaced(t_size p_playlist,const bit_array & p_mask,const pfc::list_base_const_t<t_on_items_replaced_entry> & p_data) {}
+
+	void on_playlist_created(t_size p_index,const char * p_name,t_size p_name_len) {
+		if (m_playlist != pfc_infinite && p_index <= m_playlist) m_playlist++;
+	}
+	void on_playlists_reorder(const t_size * p_order,t_size p_count) {
+		if (m_playlist < p_count) m_playlist = order_helper::g_find_reverse(p_order,m_playlist);
+		else m_playlist = pfc_infinite;
+	}
+	void on_playlists_removed(const bit_array & p_mask,t_size p_old_count,t_size p_new_count) {
+		if (m_playlist < p_old_count) {
+			const t_size playlist_before = m_playlist;
+			for(t_size walk = p_mask.find_first(true,0,p_old_count); walk < p_old_count; walk = p_mask.find_next(true,walk,p_old_count)) {
+				if (walk < playlist_before) {
+					m_playlist--;
+				} else if (walk == playlist_before) {
+					m_playlist = pfc_infinite;
+					break;
+				} else {
+					break;
+				}
+			}
+		} else {
+			m_playlist = pfc_infinite;
+		}
+	}
+
+	t_size m_playlist, m_item;
+private:
+	const bool m_trackitem;
+};