Make GenericPopUp() more readable by using more named flags instead of numerals

Defines the flags SAME_ROW (value 1) and NO_OK (value 2) for use with buttons and endmarks.
There should no functional change.
Also add a code comment where a condition depends on an uninitialised value. There is no direct harm, as both
branches do the same (that is nothing) when the value is uninitialised.

diff --git a/backend.h b/backend.h
index f0d5816..b93f81c 100644 (file)
--- a/backend.h
+++ b/backend.h
@@ -319,13 +319,17 @@ int Explode P((Board board, int fromX, int fromY, int toX, int toY));
 typedef enum { CheckBox, ComboBox, TextBox, Button, Spin, ResetButton, SaveButton,
                 FileName, PathName, Slider, Message, Fractional, Label, Break, EndMark } Control;
 
-/* Flags for Option.min: */             
-#define COMBO_CALLBACK (1 << 0)
-#define NO_GETTEXT     (1 << 1)
-                
+/* Flags Option.min used for ComboBox: */
+#define COMBO_CALLBACK (1 << 0)
+#define NO_GETTEXT     (1 << 1)
+
+/* Flags for Option.min used for Button, SaveButton, EndMark: */
+#define SAME_ROW       (1 << 0)
+#define NO_OK          (1 << 1)
+
 typedef struct _OPT {   // [HGM] options: descriptor of UCI-style option
     int value;          // current setting, starts as default
-    int min;           // Also used for flags with ComboBox
+    int min;           // Also used for flags
     int max;
     void *handle;       // for use by front end
     void *target;       // for use by front end

diff --git a/xoptions.c b/xoptions.c
index 71d9df5..648d452 100644 (file)
--- a/xoptions.c
+++ b/xoptions.c
@@ -954,7 +954,7 @@ GenericPopUp(Option *option, char *title, int dlgNr)
        if(!n) { DisplayNote(_("Engine has no options")); currentCps = NULL; return 0; }
        if(n > 50) width = 4; else if(n>24) width = 2; else width = 1;
        height = n / width + 1;
-       if(n && (currentOption[n-1].type == Button || currentOption[n-1].type == SaveButton)) currentOption[n].min = 1; // OK on same line
+       if(n && (currentOption[n-1].type == Button || currentOption[n-1].type == SaveButton)) currentOption[n].min = SAME_ROW; // OK on same line
        currentOption[n].type = EndMark; currentOption[n].target = NULL; // delimit list by callback-less end mark
     }
      i = 0;
@@ -1096,10 +1096,14 @@ GenericPopUp(Option *option, char *title, int dlgNr)
          case SaveButton:
          case Button:
            j=0;
-           XtSetArg(args[j], XtNfromVert, option[i].min & 1 ? lastrow : last);  j++;
+           if(option[i].min & SAME_ROW) {
+               XtSetArg(args[j], XtNfromVert, lastrow);  j++;
+               XtSetArg(args[j], XtNfromHoriz, last);  j++;
+           } else {
+               XtSetArg(args[j], XtNfromVert, last);  j++;
+               XtSetArg(args[j], XtNfromHoriz, NULL);  j++; lastrow = forelast;
+           }
            XtSetArg(args[j], XtNlabel, _(option[i].name));  j++;
-           if(option[i].min & 1) { XtSetArg(args[j], XtNfromHoriz, last);  j++; }
-           else  { XtSetArg(args[j], XtNfromHoriz, NULL);  j++; lastrow = forelast; }
            if(option[i].max) { XtSetArg(args[j], XtNwidth, option[i].max);  j++; }
            if(option[i].textValue) { // special for buttons of New Variant dialog
                XtSetArg(args[j], XtNsensitive, appData.noChessProgram || option[i].value < 0
@@ -1182,7 +1186,7 @@ GenericPopUp(Option *option, char *title, int dlgNr)
     for(h=0; h<height; h++) {
        i = h + c*height;
        if(option[i].type == EndMark) break;
-       if(!texts[h]) continue;
+       if(!texts[h]) continue; // Note: texts[h] can be undefined (giving errors in valgrind), but then both if's below will be false.
        j=0;
        if(option[i].type == Spin) {
            XtSetArg(args[j], XtNwidth, maxWidth);  j++;
@@ -1195,10 +1199,10 @@ GenericPopUp(Option *option, char *title, int dlgNr)
     }
   }
 
-  if(!(option[i].min & 2)) {
+  if(!(option[i].min & NO_OK)) {
     j=0;
-    if(option[i].min & 1) {
-       for(j=i-1; option[j+1].min&1 && option[j].type == Button; j--) {
+    if(option[i].min & SAME_ROW) {
+       for(j=i-1; option[j+1].min & SAME_ROW && option[j].type == Button; j--) {
            XtSetArg(args[0], XtNtop, XtChainBottom);
            XtSetArg(args[1], XtNbottom, XtChainBottom);
            XtSetValues(option[j].handle, args, 2);