Skip JSONC comments in JSONTokener

shared/src/main/java/art/arcane/volmlib/util/json/JSONTokener.java

@@ -208,19 +208,58 @@ public String next(int n) throws JSONException {
     }
 
     /**
-     * Get the next char in the string, skipping whitespace.
+     * Get the next char in the string, skipping whitespace and JSONC comments.
      *
      * @return A character, or 0 if there are no more characters.
      */
     public char nextClean() throws JSONException {
         for (; ; ) {
             char c = this.next();
+            if (c == '/' && this.skipComment()) {
+                continue;
+            }
             if (c == 0 || c > ' ') {
                 return c;
             }
         }
     }
 
+    private boolean skipComment() throws JSONException {
+        switch (this.next()) {
+            case '/':
+                this.skipLineComment();
+                return true;
+            case '*':
+                this.skipBlockComment();
+                return true;
+            default:
+                this.back();
+                return false;
+        }
+    }
+
+    private void skipLineComment() throws JSONException {
+        char c;
+        do {
+            c = this.next();
+        } while (c != '\n' && c != '\r' && c != 0);
+    }
+
+    private void skipBlockComment() throws JSONException {
+        for (; ; ) {
+            char c = this.next();
+            if (c == 0) {
+                throw this.syntaxError("Unclosed comment");
+            }
+            if (c == '*') {
+                if (this.next() == '/') {
+                    return;
+                }
+                this.back();
+            }
+        }
+    }
+
     /**
      * Return the characters up to the next close quote character. Backslash
      * processing is done. The formal JSON format does not allow strings in

shared/src/test/java/art/arcane/volmlib/util/json/JSONCommentTest.java

@@ -0,0 +1,56 @@
+package art.arcane.volmlib.util.json;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+
+public class JSONCommentTest {
+    @Test
+    public void lineCommentsAreSkippedAroundAndBetweenTokens() {
+        JSONObject object = new JSONObject("""
+                // Folder-specific settings
+                {
+                  "a": 1, // trailing note
+                  // whole-line note
+                  "b": [2, // inside array
+                        3]
+                }
+                // after root
+                """);
+
+        assertEquals(1, object.getInt("a"));
+        assertEquals(2, object.getJSONArray("b").length());
+        assertEquals(3, object.getJSONArray("b").getInt(1));
+    }
+
+    @Test
+    public void blockCommentsAreSkippedIncludingMultiLineAndStarRuns() {
+        JSONObject object = new JSONObject("""
+                /* header
+                 * spanning lines **/
+                {"a": /* before value */ 1, /* between pairs */ "b" /* before colon */ : 2}
+                """);
+
+        assertEquals(1, object.getInt("a"));
+        assertEquals(2, object.getInt("b"));
+    }
+
+    @Test
+    public void commentMarkersInsideStringsAreKept() {
+        JSONObject object = new JSONObject("{\"url\": \"https://volmit.com//x\", \"text\": \"/* not a comment */\"}");
+
+        assertEquals("https://volmit.com//x", object.getString("url"));
+        assertEquals("/* not a comment */", object.getString("text"));
+    }
+
+    @Test
+    public void unclosedBlockCommentIsASyntaxError() {
+        assertThrows(JSONException.class, () -> new JSONObject("{\"a\": 1 /* never closed"));
+    }
+
+    @Test
+    public void loneSlashIsStillASyntaxError() {
+        assertThrows(JSONException.class, () -> new JSONObject("{\"a\": 1 / \"b\": 2}"));
+    }
+}