From 1b570013155fdab411d17129f43b49b1eff44e83 Mon Sep 17 00:00:00 2001
From: Denis Molony <dmolony@users.noreply.github.com>
Date: Wed, 28 Oct 2020 15:42:48 +1000
Subject: [PATCH] allow empty pascal files

---
 .../diskbrowser/applefile/ExoBuffer.java      | 19 +++++++++++++++++++
 .../diskbrowser/pascal/FileEntry.java         |  5 +++++
 .../diskbrowser/utilities/HexFormatter.java   |  6 ++++++
 3 files changed, 30 insertions(+)

diff --git a/src/com/bytezone/diskbrowser/applefile/ExoBuffer.java b/src/com/bytezone/diskbrowser/applefile/ExoBuffer.java
index 9024fc6..f0a5ec2 100644
--- a/src/com/bytezone/diskbrowser/applefile/ExoBuffer.java
+++ b/src/com/bytezone/diskbrowser/applefile/ExoBuffer.java
@@ -31,6 +31,8 @@ public class ExoBuffer
   private int tableLo[] = new int[100];
   private int tableHi[] = new int[100];
 
+  private static boolean debug = false;
+
   // ---------------------------------------------------------------------------------//
   public ExoBuffer (byte[] inBuffer)
   // ---------------------------------------------------------------------------------//
@@ -43,12 +45,21 @@ public class ExoBuffer
       case 0x6000:
         outBuffer = new byte[0x2000];     // HGR
         break;
+
       case 0x8000:
         outBuffer = new byte[0x4000];     // DHGR
         break;
+
       case 0xA000:
         outBuffer = new byte[0x8000];     // SHR
         break;
+
+      case 0x5FF8:        // this is not working correctly - see CLODE019
+        return;
+
+      default:
+        System.out.printf ("Invalid buffer size: %04X%n",
+            Utility.getShortBigEndian (inBuffer, 0));
     }
 
     decrunch ();
@@ -67,12 +78,20 @@ public class ExoBuffer
   // ---------------------------------------------------------------------------------//
   {
     if (auxType != 0x1FF8 && auxType != 0x3FF8)
+    {
+      if (debug)
+        System.out.println ("wrong auxType");
       return false;
+    }
 
     int address = Utility.unsignedShort (buffer, buffer.length - 2);
 
     if (address != 0x6000 && address != 0x8000 && address != 0xA000)
+    {
+      if (debug)
+        System.out.printf ("wrong address: %04X%n", address);
       return false;
+    }
 
     return true;
   }
diff --git a/src/com/bytezone/diskbrowser/pascal/FileEntry.java b/src/com/bytezone/diskbrowser/pascal/FileEntry.java
index e463667..ba1ab59 100644
--- a/src/com/bytezone/diskbrowser/pascal/FileEntry.java
+++ b/src/com/bytezone/diskbrowser/pascal/FileEntry.java
@@ -65,6 +65,11 @@ public class FileEntry extends CatalogEntry
       return file;
 
     byte[] buffer = getExactBuffer ();
+    if (buffer.length == 0)
+    {
+      file = new AssemblerProgram (name, buffer, 0);    // see DC16.dsk
+      return file;
+    }
 
     switch (fileType)
     {
diff --git a/src/com/bytezone/diskbrowser/utilities/HexFormatter.java b/src/com/bytezone/diskbrowser/utilities/HexFormatter.java
index ed3e249..52bad88 100755
--- a/src/com/bytezone/diskbrowser/utilities/HexFormatter.java
+++ b/src/com/bytezone/diskbrowser/utilities/HexFormatter.java
@@ -167,6 +167,12 @@ public class HexFormatter
   {
     StringBuilder text = new StringBuilder ();
 
+    //    if (buffer.length == 0)
+    //    {
+    //      System.out.println ("empty buffer");
+    //      return text.toString ();
+    //    }
+
     for (int i = offset; i < offset + length; i++)
     {
       int c = buffer[i] & 0xFF;