engine: use stable candidate pages

strans.c

@@ -40,6 +40,64 @@ clearkouho(void)
 	im.sel = -1;
 }
 
+static void
+selectfirst(void)
+{
+	im.sel = im.nkouho > 0 ? 0 : -1;
+}
+
+static int
+pagefirst(void)
+{
+	if(im.sel < 0)
+		return 0;
+	return im.sel / Maxdisp * Maxdisp;
+}
+
+static int
+movedelta(u32int ks)
+{
+	static struct {
+		u32int key;
+		int delta;
+	} move[] = {
+		{Kup, -1}, {Kdown, 1},
+		{Kpgup, -Maxdisp}, {Kpgdown, Maxdisp},
+	};
+	int i;
+
+	for(i = 0; i < nelem(move); i++)
+		if(move[i].key == ks)
+			return move[i].delta;
+	return 0;
+}
+
+static void
+movekouho(int delta)
+{
+	if(im.sel < 0)
+		im.sel = 0;
+	else
+		im.sel += delta;
+	if(im.sel < 0)
+		im.sel = 0;
+	if(im.sel >= im.nkouho)
+		im.sel = im.nkouho - 1;
+}
+
+static int
+numberedkouho(u32int ks, u32int mod)
+{
+	int n;
+
+	if(mod != 0 || ks < '1' || ks > '9')
+		return -1;
+	n = pagefirst() + ks - '1';
+	if(n >= im.nkouho)
+		return -1;
+	return n;
+}
+
 static int
 isjp(Im *p)
 {
@@ -92,6 +150,7 @@ setkouho(Dictres *res)
 		im.kouho[i] = res->kouho[i];
 		im.nkouho++;
 	}
+	selectfirst();
 }
 
 static void
@@ -112,7 +171,7 @@ show(void)
 		   !mapget(im.l->map, &pre, &dc.pre))
 			dc.pre = pre;
 	}
-	first = im.sel >= Maxdisp ? im.sel - Maxdisp + 1 : 0;
+	first = pagefirst();
 	n = im.nkouho - first;
 	if(n > Maxdisp) n = Maxdisp;
 	dc.nkouho = n;
@@ -484,6 +543,7 @@ emojiquery(void)
 			addkouho(&res.kouho[i]);
 	}
 	search.text = rawhit || !localhit ? raw : local;
+	selectfirst();
 	show();
 }
 
@@ -566,25 +626,22 @@ picksearch(int n, Str *com)
 static int
 searchkey(u32int ks, u32int mod, Str *com)
 {
-	int n, off;
+	int n;
 	Rune c;
 
 	if(ismodkey(ks))
 		return 0;
-	if(ks == Kdown || ks == Kup){
+	n = movedelta(ks);
+	if(n != 0){
 		if(im.nkouho == 0)
 			return 1;
-		if(ks == Kdown && im.sel < im.nkouho - 1)
-			im.sel++;
-		if(ks == Kup && im.sel > 0)
-			im.sel--;
+		movekouho(n);
 		show();
 		return 1;
 	}
-	n = ks - '1';
-	off = im.sel >= Maxdisp ? im.sel - Maxdisp + 1 : 0;
-	if(n >= 0 && n < Maxdisp && off + n < im.nkouho && mod == 0){
-		picksearch(off + n, com);
+	n = numberedkouho(ks, mod);
+	if(n >= 0){
+		picksearch(n, com);
 		return 1;
 	}
 	if(ks == Ktab){
@@ -655,29 +712,24 @@ searchkey(u32int ks, u32int mod, Str *com)
 static int
 keystroke(u32int ks, u32int mod, Str *com)
 {
-	int n, off;
+	int n;
 	Rune c;
 
 	if(ismodkey(ks))
 		return 0;
 	if(search.lang)
 		return searchkey(ks, mod, com);
-	if(ks == Kdown || ks == Kup){
+	n = movedelta(ks);
+	if(n != 0){
 		if(im.nkouho == 0)
 			return 0;
-		if(ks == Kdown && im.sel < im.nkouho - 1)
-			im.sel++;
-		if(ks == Kup && im.sel >= 0)
-			im.sel--;
+		movekouho(n);
 		show();
 		return 1;
 	}
-	n = ks - '1';
-	off = 0;
-	if(im.sel >= Maxdisp)
-		off = im.sel - Maxdisp + 1;
-	if(n >= 0 && n < Maxdisp && off + n < im.nkouho && mod == 0){
-		sappend(com, &im.kouho[off + n]);
+	n = numberedkouho(ks, mod);
+	if(n >= 0){
+		sappend(com, &im.kouho[n]);
 		reset();
 		return 1;
 	}
@@ -769,6 +821,7 @@ init(void)
 {
 	memset(&im, 0, sizeof(im));
 	im.l = getlang(LangEN);
+	im.sel = -1;
 	memset(&search, 0, sizeof search);
 	memset(&caret, 0, sizeof caret);
 	activeowner = nil;