sonar fix - reduce complexity by using constants

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1744006 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/poifs/storage/HeaderBlock.java

@@ -40,6 +40,36 @@ import org.apache.poi.util.ShortField;
  * The block containing the archive header
  */
 public final class HeaderBlock implements HeaderBlockConstants {
+    private static final byte[] MAGIC_BIFF2 = {
+        0x09, 0x00, // sid=0x0009
+        0x04, 0x00, // size=0x0004
+        0x00, 0x00, // unused
+        0x70, 0x00  // 0x70 = multiple values
+    };
+
+    private static final byte[] MAGIC_BIFF3 = {
+        0x09, 0x02, // sid=0x0209
+        0x06, 0x00, // size=0x0006
+        0x00, 0x00, // unused
+        0x70, 0x00  // 0x70 = multiple values
+    };
+
+    private static final byte[] MAGIC_BIFF4a = {
+        0x09, 0x04, // sid=0x0409
+        0x06, 0x00, // size=0x0006
+        0x00, 0x00, // unused
+        0x70, 0x00  // 0x70 = multiple values
+    };
+
+    private static final byte[] MAGIC_BIFF4b = {
+        0x09, 0x04, // sid=0x0409
+        0x06, 0x00, // size=0x0006
+        0x00, 0x00, // unused
+        0x00, 0x01
+    };
+
+    private static final byte _default_value = ( byte ) 0xFF;
+
     /**
 	 * What big block size the file uses. Most files
 	 *  use 512 bytes, but a few use 4096
@@ -85,8 +115,6 @@ public final class HeaderBlock implements HeaderBlockConstants {
 	 */
 	private final byte[] _data;
 	
-   private static final byte _default_value = ( byte ) 0xFF;
-
 	/**
 	 * create a new HeaderBlockReader from an InputStream
 	 *
@@ -113,58 +141,40 @@ public final class HeaderBlock implements HeaderBlockConstants {
 	}
 	
 	private HeaderBlock(byte[] data) throws IOException {
-	   this._data = data;
+	   this._data = data.clone();
 	   
 		// verify signature
 		long signature = LittleEndian.getLong(_data, _signature_offset);
 
 		if (signature != _signature) {
 			// Is it one of the usual suspects?
-			byte[] OOXML_FILE_HEADER = POIFSConstants.OOXML_FILE_HEADER;
+			if (cmp(POIFSConstants.OOXML_FILE_HEADER, data)) {
-			if (_data[0] == OOXML_FILE_HEADER[0] &&
+				throw new OfficeXmlFileException("The supplied data appears to be in the Office 2007+ XML. "
-				_data[1] == OOXML_FILE_HEADER[1] &&
+			        + "You are calling the part of POI that deals with OLE2 Office Documents. "
-				_data[2] == OOXML_FILE_HEADER[2] &&
+			        + "You need to call a different part of POI to process this data (eg XSSF instead of HSSF)");
-				_data[3] == OOXML_FILE_HEADER[3]) {
-				throw new OfficeXmlFileException("The supplied data appears to be in the Office 2007+ XML. You are calling the part of POI that deals with OLE2 Office Documents. You need to call a different part of POI to process this data (eg XSSF instead of HSSF)");
 			}
 			
-            byte[] RAW_XML_FILE_HEADER = POIFSConstants.RAW_XML_FILE_HEADER;
+            if (cmp(POIFSConstants.RAW_XML_FILE_HEADER, data)) {
-            if (_data[0] == RAW_XML_FILE_HEADER[0] &&
+                throw new NotOLE2FileException("The supplied data appears to be a raw XML file. "
-                _data[1] == RAW_XML_FILE_HEADER[1] &&
+                    + "Formats such as Office 2003 XML are not supported");
-                _data[2] == RAW_XML_FILE_HEADER[2] &&
-                _data[3] == RAW_XML_FILE_HEADER[3] &&
-                _data[4] == RAW_XML_FILE_HEADER[4]) {
-                throw new NotOLE2FileException("The supplied data appears to be a raw XML file. Formats such as Office 2003 XML are not supported");
             }
             
-            if (_data[0] == 0x09 && _data[1] == 0x00 && // sid=0x0009
-                _data[2] == 0x04 && _data[3] == 0x00 && // size=0x0004
-                _data[4] == 0x00 && _data[5] == 0x00 && // unused
-               (_data[6] == 0x10 || _data[6] == 0x20 || _data[6] == 0x40) &&
-                _data[7] == 0x00) {
             // BIFF2 raw stream
-                throw new OldExcelFormatException("The supplied data appears to be in BIFF2 format. " +
+            if (cmp(MAGIC_BIFF2, data)) {
-                        "HSSF only supports the BIFF8 format, try OldExcelExtractor");
+                throw new OldExcelFormatException("The supplied data appears to be in BIFF2 format. "
+                    + "HSSF only supports the BIFF8 format, try OldExcelExtractor");
             }
-            if (_data[0] == 0x09 && _data[1] == 0x02 && // sid=0x0209
+            
-                _data[2] == 0x06 && _data[3] == 0x00 && // size=0x0006
-                _data[4] == 0x00 && _data[5] == 0x00 && // unused
-               (_data[6] == 0x10 || _data[6] == 0x20 || _data[6] == 0x40) &&
-                _data[7] == 0x00) {
             // BIFF3 raw stream
-                throw new OldExcelFormatException("The supplied data appears to be in BIFF3 format. " +
+            if (cmp(MAGIC_BIFF3, data)) {
-                        "HSSF only supports the BIFF8 format, try OldExcelExtractor");
+                throw new OldExcelFormatException("The supplied data appears to be in BIFF3 format. "
+                    + "HSSF only supports the BIFF8 format, try OldExcelExtractor");
             }
-            if (_data[0] == 0x09 && _data[1] == 0x04 && // sid=0x0409
+            
-                _data[2] == 0x06 && _data[3] == 0x00 && // size=0x0006
-                _data[4] == 0x00 && _data[5] == 0x00) { // unused
-                if (((_data[6] == 0x10 || _data[6] == 0x20 || _data[6] == 0x40) &&
-                      _data[7] == 0x00) ||
-                    (_data[6] == 0x00 && _data[7] == 0x01)) {
             // BIFF4 raw stream
-                    throw new OldExcelFormatException("The supplied data appears to be in BIFF4 format. " +
+            if (cmp(MAGIC_BIFF4a, data) || cmp(MAGIC_BIFF4b, data)) {
-                            "HSSF only supports the BIFF8 format, try OldExcelExtractor");
+                throw new OldExcelFormatException("The supplied data appears to be in BIFF4 format. "
-                }
+                    + "HSSF only supports the BIFF8 format, try OldExcelExtractor");
             }
 
 			// Give a generic error if the OLE2 signature isn't found
@@ -221,7 +231,7 @@ public final class HeaderBlock implements HeaderBlockConstants {
       new IntegerField(0x34, 0, _data);
       new IntegerField(0x38, 0x1000, _data);
       
-      // Initialise the variables
+      // Initialize the variables
       _bat_count = 0;
       _sbat_count = 0;
       _xbat_count = 0;
@@ -394,9 +404,7 @@ public final class HeaderBlock implements HeaderBlockConstants {
     * @exception IOException on problems writing to the specified
     *            stream
     */
-   void writeData(final OutputStream stream)
+   void writeData(final OutputStream stream) throws IOException {
-       throws IOException
-   {
       // Update the counts and start positions 
       new IntegerField(_bat_count_offset,      _bat_count, _data);
       new IntegerField(_property_start_offset, _property_start, _data);
@@ -413,4 +421,15 @@ public final class HeaderBlock implements HeaderBlockConstants {
          stream.write(0);
       }
    }
+   
+   private static boolean cmp(byte[] magic, byte[] data) {
+       int i=0;
+       for (byte m : magic) {
+           byte d = data[i++];
+           if (!(d == m || (m == 0x70 && (d == 0x10 || d == 0x20 || d == 0x40)))) {
+               return false;
+           }
+       }
+       return true;
+   }
 }