fix handling of numeric column indexes for v2007 databases

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/branches/newformats@449 f203690c-595d-4dc9-a70b-905162fa7fd2

2 files changed, 34 insertions, 7 deletions

diff --git a/src/java/com/healthmarketscience/jackcess/Index.java b/src/java/com/healthmarketscience/jackcess/Index.java
index b629049..f72377a 100644
--- a/src/java/com/healthmarketscience/jackcess/Index.java
+++ b/src/java/com/healthmarketscience/jackcess/Index.java
@@ -1540,17 +1540,31 @@ public abstract class Index implements Comparable<Index> {
       boolean isNegative = ((valueBytes[0] & 0x80) != 0);
 
       // bit twiddling rules:
-      // isAsc && !isNeg => setReverseSignByte
-      // isAsc && isNeg => flipBytes, setReverseSignByte
-      // !isAsc && !isNeg => flipBytes, setReverseSignByte
-      // !isAsc && isNeg => setReverseSignByte
+      // isAsc && !isNeg => setReverseSignByte             => FF 00 00 ...
+      // isAsc && isNeg => flipBytes, setReverseSignByte   => 00 FF FF ...
+      // !isAsc && !isNeg => flipBytes, setReverseSignByte => FF FF FF ...
+      // !isAsc && isNeg => setReverseSignByte             => 00 00 00 ...
       
+      // v2007 bit twiddling rules:
+      // isAsc && !isNeg => setSignByte 0xFF            => FF 00 00 ...
+      // isAsc && isNeg => setSignByte 0xFF, flipBytes  => 00 FF FF ...
+      // !isAsc && !isNeg => setSignByte 0xFF           => FF 00 00 ...
+      // !isAsc && isNeg => setSignByte 0xFF, flipBytes => 00 FF FF ...
+
+      boolean alwaysRevFirstByte = getColumn().getFormat().REVERSE_FIRST_BYTE_IN_DESC_NUMERIC_INDEXES;
+      if(alwaysRevFirstByte) {
+        // reverse the sign byte (before any byte flipping)
+        valueBytes[0] = (byte)0xFF;
+      }
+
       if(isNegative == isAscending()) {
         flipBytes(valueBytes);
       }
 
-      // reverse the sign byte (after any previous byte flipping)
-      valueBytes[0] = (isNegative ? (byte)0x00 : (byte)0xFF);
+      if(!alwaysRevFirstByte) {
+        // reverse the sign byte (after any previous byte flipping)
+        valueBytes[0] = (isNegative ? (byte)0x00 : (byte)0xFF);
+      }
       
       bout.write(valueBytes);
     }    
diff --git a/src/java/com/healthmarketscience/jackcess/JetFormat.java b/src/java/com/healthmarketscience/jackcess/JetFormat.java
index afb1804..62ce992 100644
--- a/src/java/com/healthmarketscience/jackcess/JetFormat.java
+++ b/src/java/com/healthmarketscience/jackcess/JetFormat.java
@@ -130,6 +130,8 @@ public abstract class JetFormat {
   public final int MAX_TABLE_NAME_LENGTH;
   public final int MAX_COLUMN_NAME_LENGTH;
   public final int MAX_INDEX_NAME_LENGTH;
+
+  public final boolean REVERSE_FIRST_BYTE_IN_DESC_NUMERIC_INDEXES;
   
   public final Charset CHARSET;
   
@@ -230,7 +232,8 @@ public abstract class JetFormat {
     MAX_TABLE_NAME_LENGTH = defineMaxTableNameLength();
     MAX_COLUMN_NAME_LENGTH = defineMaxColumnNameLength();
     MAX_INDEX_NAME_LENGTH = defineMaxIndexNameLength();
-
+    
+    REVERSE_FIRST_BYTE_IN_DESC_NUMERIC_INDEXES = defineReverseFirstByteInDescNumericIndexes();
     
     CHARSET = defineCharset();
   }
@@ -305,6 +308,8 @@ public abstract class JetFormat {
   
   protected abstract Charset defineCharset();
 
+  protected abstract boolean defineReverseFirstByteInDescNumericIndexes();
+
   @Override
   public String toString() {
     return _name;
@@ -449,6 +454,9 @@ public abstract class JetFormat {
     protected int defineMaxIndexNameLength() { return 64; }
       
     @Override
+    protected boolean defineReverseFirstByteInDescNumericIndexes() { return false; }
+
+    @Override
     protected Charset defineCharset() { return Charset.forName("UTF-16LE"); }
   }
   
@@ -462,5 +470,10 @@ public abstract class JetFormat {
       private Jet5Format() {
         super("VERSION_5");
       }
+
+    @Override
+    protected boolean defineReverseFirstByteInDescNumericIndexes() { return true; }
+
   }
+
 }