From cbaf52fbe1aaf7fc34cd585739b4f9fc10af1ad8 Mon Sep 17 00:00:00 2001
From: PeterN <peter@fuzzle.org>
Date: Sat, 2 Mar 2019 17:08:45 +0000
Subject: Codechange: Sort and filter sign names directly rather than through
 string system. (#7304)

This provides a notable performance benefit in the Sign List window when there are many signs.
---
 src/signs_gui.cpp | 48 ++++++++++++++++++++++++++----------------------
 1 file changed, 26 insertions(+), 22 deletions(-)

(limited to 'src/signs_gui.cpp')

diff --git a/src/signs_gui.cpp b/src/signs_gui.cpp
index 15adef089..56af6e665 100644
--- a/src/signs_gui.cpp
+++ b/src/signs_gui.cpp
@@ -41,11 +41,11 @@ struct SignList {
 	 */
 	typedef GUIList<const Sign *, StringFilter &> GUISignList;
 
-	static const Sign *last_sign;
 	GUISignList signs;
 
 	StringFilter string_filter;                                       ///< The match string to be used when the GUIList is (re)-sorted.
 	static bool match_case;                                           ///< Should case sensitive matching be used?
+	static char default_name[64];                                     ///< Default sign name, used if Sign::name is NULL.
 
 	/**
 	 * Creates a SignList with filtering disabled by default.
@@ -74,19 +74,17 @@ struct SignList {
 	/** Sort signs by their name */
 	static int CDECL SignNameSorter(const Sign * const *a, const Sign * const *b)
 	{
-		static char buf_cache[64];
-		char buf[64];
+		/* Signs are very very rarely using the default text, but there can also be
+		 * a lot of them. Therefore a worthwhile performance gain can be made by
+		 * directly comparing Sign::name instead of going through the string
+		 * system for each comparison. */
+		const char *a_name = (*a)->name;
+		const char *b_name = (*b)->name;
 
-		SetDParam(0, (*a)->index);
-		GetString(buf, STR_SIGN_NAME, lastof(buf));
+		if (a_name == NULL) a_name = SignList::default_name;
+		if (b_name == NULL) b_name = SignList::default_name;
 
-		if (*b != last_sign) {
-			last_sign = *b;
-			SetDParam(0, (*b)->index);
-			GetString(buf_cache, STR_SIGN_NAME, lastof(buf_cache));
-		}
-
-		int r = strnatcmp(buf, buf_cache); // Sort by name (natural sorting).
+		int r = strnatcmp(a_name, b_name); // Sort by name (natural sorting).
 
 		return r != 0 ? r : ((*a)->index - (*b)->index);
 	}
@@ -94,21 +92,18 @@ struct SignList {
 	void SortSignsList()
 	{
 		if (!this->signs.Sort(&SignNameSorter)) return;
-
-		/* Reset the name sorter sort cache */
-		this->last_sign = NULL;
 	}
 
 	/** Filter sign list by sign name */
 	static bool CDECL SignNameFilter(const Sign * const *a, StringFilter &filter)
 	{
-		/* Get sign string */
-		char buf1[MAX_LENGTH_SIGN_NAME_CHARS * MAX_CHAR_LENGTH];
-		SetDParam(0, (*a)->index);
-		GetString(buf1, STR_SIGN_NAME, lastof(buf1));
+		/* Same performance benefit as above for sorting. */
+		const char *a_name = (*a)->name;
+
+		if (a_name == NULL) a_name = SignList::default_name;
 
 		filter.ResetState();
-		filter.AddLine(buf1);
+		filter.AddLine(a_name);
 		return filter.GetState();
 	}
 
@@ -138,8 +133,8 @@ struct SignList {
 	}
 };
 
-const Sign *SignList::last_sign = NULL;
 bool SignList::match_case = false;
+char SignList::default_name[64];
 
 /** Enum referring to the Hotkeys in the sign list window */
 enum SignListHotkeys {
@@ -171,6 +166,15 @@ struct SignListWindow : Window, SignList {
 		this->BuildSortSignList();
 	}
 
+	virtual void OnInit()
+	{
+		/* Default sign name, used if Sign::name is NULL. */
+		GetString(SignList::default_name, STR_DEFAULT_SIGN_NAME, lastof(SignList::default_name));
+		this->signs.ForceResort();
+		this->SortSignsList();
+		this->SetDirty();
+	}
+
 	/**
 	 * This function sets the filter string of the sign list. The contents of
 	 * the edit widget is not updated by this function. Depending on if the
@@ -188,7 +192,7 @@ struct SignListWindow : Window, SignList {
 
 	virtual void OnPaint()
 	{
-		if (this->signs.NeedRebuild()) this->BuildSortSignList();
+		if (!this->IsShaded() && this->signs.NeedRebuild()) this->BuildSortSignList();
 		this->DrawWidgets();
 	}
 
-- 
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