Correct divide-by-zero test issue

Author: ghidra1

Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/equate/AbstractConvertAction.java

@@ -42,10 +42,6 @@ public AbstractConvertAction(EquatePlugin plugin, String actionName, boolean isS
 		this.isSigned = isSigned;
 		setPopupMenuData(new MenuData(new String[] { "Convert", "" }, "Convert"));
 		setEnabled(true);
-		JMenuItem item = new JMenuItem();
-		Font font = item.getFont();
-		metrics = plugin.getTool().getActiveWindow().getFontMetrics(font);
-
 	}
 
 	@Override
@@ -132,14 +128,28 @@ protected final boolean isSignedChoice() {
 		return isSigned;
 	}
 
+	private int stringWidth(String s) {
+		if (metrics == null) {
+			JMenuItem item = new JMenuItem();
+			Font font = item.getFont();
+			metrics = plugin.getTool().getActiveWindow().getFontMetrics(font);
+		}
+		int w = metrics.stringWidth(s);
+		if (w == 0) {
+			// use default computation if metrics report 0
+			return 10 * s.length();
+		}
+		return w;
+	}
+
 	String getStandardLengthString(String baseString) {
-		int baseWidth = metrics.stringWidth(baseString);
-		int spaceWidth = metrics.stringWidth(" ");
+		int baseWidth = stringWidth(baseString);
+		int spaceWidth = stringWidth(" ");
 		int paddingSize = (140 - baseWidth) / spaceWidth;
 		if (paddingSize <= 0) {
 			return baseString;
 		}
-		StringBuffer buf = new StringBuffer(baseString);
+		StringBuilder buf = new StringBuilder(baseString);
 		for (int i = 0; i < paddingSize; i++) {
 			buf.append(" ");
 		}