refactor: make Terminal.SCROLL_BACK_COUNT static final

src/main/java/li/cil/oc2/common/vm/terminal/Terminal.java

@@ -57,7 +57,7 @@
     private transient int lastSentPaletteRevision = -1;
     public byte style;
 
-    public int SCROLL_BACK_COUNT = 20;
+    public static final int SCROLL_BACK_COUNT = 20;
     public transient ByteArrayFIFOQueue input = new ByteArrayFIFOQueue(32);
     // DECCOLM dynamic width; setWidth reallocates buffers. Transient: re-inits to WIDTH on load.
     public transient int width = WIDTH;
@@ -363,7 +363,7 @@
     }
 
     /** Dirty state since the last consume: full-refresh request plus changed buffer rows. */
     public record NetworkDirty(boolean fullRefresh, int[] rows) {}
 
     public NetworkDirty consumeNetworkDirty() {
         networkDirtyLock.lock();

src/main/java/li/cil/oc2/common/vm/terminal/TerminalDiff.java

@@ -53,15 +53,15 @@
     private static final int PALETTE_SIZE = 256;
 
     /**
      * @param rows    absolute buffer row indices (alt-buffer: screen rows 0..23)
      * @param rowData serialized cell data, one array per entry of {@code rows}
      */
     public record Snapshot(
             boolean reset,
             int width,
             boolean altBuffer,
             int[] rows,
             byte[][] rowData,
             int cursorX,
             int cursorY,
             int lastRowToDisplay,
@@ -70,7 +70,7 @@
             boolean cursorVisible,
             boolean bell,
             long inputModes,
             int[] palette) {}
 
     /**
      * Private-mode flags that affect client-side rendering or input handling beyond the
@@ -176,7 +176,7 @@
         }
         // Main buffer: the currently displayed scrollback window.
         final int first = Math.max(0, terminal.lastRowToDisplay - Terminal.HEIGHT);
-        final int count = Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT - first;
+        final int count = Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT - first;
         final int[] rows = new int[Math.min(Terminal.HEIGHT, count)];
         for (int i = 0; i < rows.length; i++) {
             rows[i] = first + i;
@@ -242,7 +242,7 @@
 
     /** Packs mode ordinal (3 bits) plus 8-bit R/G/B into a single varint-friendly value. */
     private static int packColor(final ColorData color) {
         return (color.mode.ordinal() & 0x7)
                 | (color.r & 0xFF) << 3
                 | (color.g & 0xFF) << 11
                 | (color.b & 0xFF) << 19;
@@ -360,7 +360,7 @@
     private static void deserializeRow(
             final Terminal terminal, final boolean alt, final int row, final byte[] data) {
         if (row < 0
-                || (alt ? row >= Terminal.HEIGHT : row >= Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT)) {
+                || (alt ? row >= Terminal.HEIGHT : row >= Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT)) {
             return;
         }
         final ByteBuffer buf = ByteBuffer.wrap(data).order(ByteOrder.LITTLE_ENDIAN);

src/main/java/li/cil/oc2/common/vm/terminal/buffer/TerminalBufferScrolling.java

@@ -20,7 +20,7 @@ public void incrementLastLineToDisplay(boolean scroll) {
             terminal.lastRowToDisplayMax =
                     Math.min(
                             terminal.lastRowToDisplayMax + 1,
-                            Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT);
+                            Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT);
         } else if (terminal.lastRowToDisplay == terminal.lastRowToDisplayMax) {
             return;
         }
@@ -53,7 +53,7 @@ public void shiftUp(int count) {
         if (terminal.currentPrivateModeState.isAltBufferEnabled()) {
             shiftLines(terminal.scrollFirst + 1, terminal.scrollLast, -count);
         } else {
-            if (terminal.lastRowToDisplay == Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT
+            if (terminal.lastRowToDisplay == Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT
                     || terminal.scrollLast != Terminal.HEIGHT - 1
                     || terminal.scrollFirst != 0) {
                 shiftLines(
@@ -65,7 +65,7 @@ public void shiftUp(int count) {
                                 : 1,
                         terminal.scrollLast != Terminal.HEIGHT - 1
                                 ? terminal.scrollLast + terminal.lastRowToDisplayMax - Terminal.HEIGHT
-                                : (Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT) - 1,
+                                : (Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT) - 1,
                         -count);
             }
         }

src/main/java/li/cil/oc2/common/vm/terminal/escapes/csi/CH8.java

@@ -32,7 +32,7 @@ public void execute(final int[] args, final int argsCount, final CSIState state)
             final int n = Math.min(args[0], Terminal.HEIGHT);
             for (int i = 0; i < n; i++) {
                 if (terminal.lastRowToDisplay
-                        < Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT) {
+                        < Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT) {
                     terminal.bufferManager.incrementLastLineToDisplay();
                 }
                 terminal.bufferManager.shiftUpOne();

src/test/java/li/cil/oc2/common/vm/terminal/TerminalBufferTest.java

@@ -57,7 +57,7 @@ void initialBufferState() {
         assertEquals(0, terminal.y);
         assertEquals(24, terminal.lastRowToDisplay);
         assertEquals(24, terminal.lastRowToDisplayMax);
-        assertEquals(Terminal.WIDTH * Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT, terminal.buffer.length);
+        assertEquals(Terminal.WIDTH * Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT, terminal.buffer.length);
         assertEquals(' ', charAt(0, 0));
         assertEquals(' ', charAt(Terminal.WIDTH - 1, Terminal.HEIGHT - 1));
         assertFalse(terminal.currentPrivateModeState.isAltBufferEnabled());
@@ -1442,7 +1442,7 @@ void deccolmSwitchesColumnWidthAndClearsScreen() {
         write(terminal, CSI + "?3h");
         assertTrue(terminal.currentPrivateModeState.DECCOLM, "?3h enables DECCOLM");
         assertEquals(132, terminal.getTerminalWidth(), "DECCOLM switches to 132 columns");
-        final int expected132 = 132 * Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT;
+        final int expected132 = 132 * Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT;
         assertEquals(expected132, terminal.buffer.length, "buffers reallocate to 132 columns");
         assertEquals(0xFFFFFF, renderer.dirtyMask.get() & 0xFFFFFF,
             "DECCOLM must redraw the whole screen");
@@ -1464,7 +1464,7 @@ void deccolmSwitchesColumnWidthAndClearsScreen() {
         write(terminal, CSI + "?3l");
         assertFalse(terminal.currentPrivateModeState.DECCOLM, "?3l disables DECCOLM");
         assertEquals(Terminal.WIDTH, terminal.getTerminalWidth(), "reset returns to 80 columns");
-        final int expected80 = Terminal.WIDTH * Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT;
+        final int expected80 = Terminal.WIDTH * Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT;
         assertEquals(expected80, terminal.buffer.length, "buffers reallocate back to 80 columns");
     }
 
@@ -1590,7 +1590,7 @@ void scrollDownAtFullScrollbackDoesNotOverflow() {
         // SD (CSI T) / RI used to arraycopy past the physical buffer end
         // (AIOOBE under lock in putOutput -> terminal dead forever).
         writeMarkers();
-        assertEquals(Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT, terminal.lastRowToDisplayMax,
+        assertEquals(Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT, terminal.lastRowToDisplayMax,
             "precondition: scrollback filled to cap");
         // Marker two rows above the discarded pair: survives the shift onto the last row.
         final int bottomMarkerRow = Terminal.HEIGHT - 3;
@@ -1630,7 +1630,7 @@ void scrollUpDownWithHugeCountTerminates() {
     private void writeMarkers() {
         // Grow the scrollback window to its hard cap (HEIGHT * SCROLL_BACK_COUNT rows).
         final StringBuilder feed = new StringBuilder();
-        feed.append("\n".repeat(Terminal.HEIGHT * terminal.SCROLL_BACK_COUNT));
+        feed.append("\n".repeat(Terminal.HEIGHT * Terminal.SCROLL_BACK_COUNT));
         write(terminal, feed.toString());
     }
 }