Merge pull request #132 from MichelZ/mize/improve_uniqueid

Improve unique sector index validation

Author: ironfede

sources/OpenMcdf/CompoundFile.cs

@@ -1325,12 +1325,15 @@ int nextSecID
 
         private void EnsureUniqueSectorIndex(int nextSecID, HashSet<int> processedSectors)
         {
-            if (processedSectors.Contains(nextSecID) && this.validationExceptionEnabled)
+            if (!this.validationExceptionEnabled)
             {
-                throw new CFCorruptedFileException("The file is corrupted.");
+                return;
             }
 
-            processedSectors.Add(nextSecID);
+            if (!processedSectors.Add(nextSecID))
+            {
+                throw new CFCorruptedFileException("The file is corrupted.");
+            }
         }
 
         /// <summary>