From 26316a82a9a0557f0bacbc708c441da83a72df41 Mon Sep 17 00:00:00 2001
From: Denis Molony <dmolony@users.noreply.github.com>
Date: Sat, 24 Jul 2021 20:59:00 +1000
Subject: [PATCH] better CP/M format checker

---
 src/com/bytezone/diskbrowser/cpm/CPMDisk.java | 55 +++++++++++++++++++
 .../bytezone/diskbrowser/disk/AppleDisk.java  |  7 ++-
 .../diskbrowser/disk/DiskFactory.java         |  6 +-
 .../bytezone/diskbrowser/infocom/ZObject.java |  2 -
 4 files changed, 62 insertions(+), 8 deletions(-)

diff --git a/src/com/bytezone/diskbrowser/cpm/CPMDisk.java b/src/com/bytezone/diskbrowser/cpm/CPMDisk.java
index 6340192..16afbeb 100644
--- a/src/com/bytezone/diskbrowser/cpm/CPMDisk.java
+++ b/src/com/bytezone/diskbrowser/cpm/CPMDisk.java
@@ -1,6 +1,7 @@
 package com.bytezone.diskbrowser.cpm;
 
 import java.awt.Color;
+import java.util.ArrayList;
 import java.util.List;
 
 import javax.swing.tree.DefaultMutableTreeNode;
@@ -211,6 +212,60 @@ public class CPMDisk extends AbstractFormattedDisk
   // ---------------------------------------------------------------------------------//
   public static boolean isCorrectFormat (AppleDisk disk)
   // ---------------------------------------------------------------------------------//
+  {
+    boolean debug = false;
+
+    disk.setInterleave (3);
+
+    // collect catalog sectors
+    List<DiskAddress> catalog = new ArrayList<> ();
+    for (int i = 0; i < 8; i++)
+      catalog.add (disk.getDiskAddress (3, i));
+    byte[] buffer = disk.readBlocks (catalog);
+
+    if (debug)
+      System.out.println (HexFormatter.format (buffer));
+
+    for (int i = 0; i < 2; i++)
+    {
+      int start = i * 1024;
+      int end = start + 1024;
+
+      for (int ptr = start; ptr < end; ptr += 32)
+      {
+        if (buffer[ptr] == (byte) EMPTY_BYTE_VALUE)
+        {
+          if (buffer[ptr + 1] == (byte) EMPTY_BYTE_VALUE)     // finished this block
+            break;
+          continue;                                           // deleted file?
+        }
+
+        int userNo = buffer[ptr] & 0xFF;
+        if (userNo > 31)
+          return false;
+
+        for (int j = 1; j < 12; j++)
+        {
+          int ch = buffer[ptr + j] & 0xFF;
+          if (ch < 32 || ch > 126)                            // invalid ascii
+            return false;
+        }
+
+        if (debug)
+        {
+          String fileName = new String (buffer, ptr + 1, 8);
+          String fileType = new String (buffer, ptr + 9, 3);
+          System.out.printf ("%2d  %s %s%n", userNo, fileName, fileType);
+        }
+      }
+    }
+
+    return true;
+  }
+
+  // ---------------------------------------------------------------------------------//
+  private static boolean isCorrectFormat2 (AppleDisk disk)
+  // ---------------------------------------------------------------------------------//
   {
     disk.setInterleave (3);
 
diff --git a/src/com/bytezone/diskbrowser/disk/AppleDisk.java b/src/com/bytezone/diskbrowser/disk/AppleDisk.java
index 12defc3..4a33f9c 100755
--- a/src/com/bytezone/diskbrowser/disk/AppleDisk.java
+++ b/src/com/bytezone/diskbrowser/disk/AppleDisk.java
@@ -50,9 +50,9 @@ public class AppleDisk implements Disk
   private static int[][] interleaveSector = //
       { { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
           22, 23, 24, 25, 26, 27, 28, 29, 30, 31 },                     // None
-        { 0, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 15 },       // Prodos/Pascal
-        { 0, 13, 11, 9, 7, 5, 3, 1, 14, 12, 10, 8, 6, 4, 2, 15 },       // Infocom
-        { 0, 6, 12, 3, 9, 15, 14, 5, 11, 2, 8, 7, 13, 4, 10, 1 } };     // CPM
+          { 0, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 15 },       // Prodos/Pascal
+          { 0, 13, 11, 9, 7, 5, 3, 1, 14, 12, 10, 8, 6, 4, 2, 15 },       // Infocom
+          { 0, 6, 12, 3, 9, 15, 14, 5, 11, 2, 8, 7, 13, 4, 10, 1 } };     // CPM
 
   // Physical disk interleave:
   // Info from http://www.applelogic.org/TheAppleIIEGettingStarted.html
@@ -468,6 +468,7 @@ public class AppleDisk implements Disk
         readBuffer (da, buffer, ptr);
       ptr += sectorSize;
     }
+
     return buffer;
   }
 
diff --git a/src/com/bytezone/diskbrowser/disk/DiskFactory.java b/src/com/bytezone/diskbrowser/disk/DiskFactory.java
index 56e304c..13a7b8d 100755
--- a/src/com/bytezone/diskbrowser/disk/DiskFactory.java
+++ b/src/com/bytezone/diskbrowser/disk/DiskFactory.java
@@ -556,6 +556,9 @@ public class DiskFactory
     if (disk == null)
       disk = checkPascalDisk (appleDisk512);
 
+    if (disk == null)
+      disk = checkCPMDisk (appleDisk256);
+
     if (disk == null)
     {
       disk2 = checkInfocomDisk (appleDisk256);
@@ -563,9 +566,6 @@ public class DiskFactory
         disk = disk2;
     }
 
-    if (disk == null)
-      disk = checkCPMDisk (appleDisk256);       // checks almost nothing
-
     if (disk == null)
       disk = new DataDisk (appleDisk256);
 
diff --git a/src/com/bytezone/diskbrowser/infocom/ZObject.java b/src/com/bytezone/diskbrowser/infocom/ZObject.java
index 7a4a87e..f8fd191 100755
--- a/src/com/bytezone/diskbrowser/infocom/ZObject.java
+++ b/src/com/bytezone/diskbrowser/infocom/ZObject.java
@@ -57,9 +57,7 @@ class ZObject extends AbstractFile implements Comparable<ZObject>
     propertyTablePtr = header.getWord (offset + 7);
     int ptr = propertyTablePtr;
     int nameLength = header.getByte (ptr) * 2;
-    System.out.printf ("was %s%n", this.getName ());
     setName (nameLength == 0 ? "<<" + id + ">>" : new ZString (header, ++ptr).value);
-    System.out.printf ("now %s%n", this.getName ());
     ptr += nameLength;
 
     // read each property