Transfer code from svn to gitlab.alfresco.com

src/main/java/org/alfresco/encoding/BomCharactersetFinder.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2005-2010 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.alfresco.encoding;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.Charset;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * Byte Order Marker encoding detection.
+ * 
+ * @since 2.1
+ * @author Pacific Northwest National Lab
+ * @author Derek Hulley
+ */
+public class BomCharactersetFinder extends AbstractCharactersetFinder
+{
+    private static Log logger = LogFactory.getLog(BomCharactersetFinder.class);
+    
+    @Override
+    public void setBufferSize(int bufferSize)
+    {
+        logger.warn("Setting the buffersize has no effect for charset finder: " + BomCharactersetFinder.class.getName());
+    }
+
+    /**
+     * @return          Returns 64
+     */
+    @Override
+    protected int getBufferSize()
+    {
+        return 64;
+    }
+
+    /**
+     * Just searches the Byte Order Marker, i.e. the first three characters for a sign of
+     * the encoding.
+     */
+    protected Charset detectCharsetImpl(byte[] buffer) throws Exception
+    {
+        Charset charset = null;
+        ByteArrayInputStream bis = null;
+        try
+        {
+            bis = new ByteArrayInputStream(buffer);
+            bis.mark(3);
+            char[] byteHeader = new char[3];
+            InputStreamReader in = new InputStreamReader(bis);
+            int bytesRead = in.read(byteHeader);
+            bis.reset();
+
+            if (bytesRead < 2)
+            {
+                // ASCII
+                charset = Charset.forName("Cp1252");
+            }
+            else if (
+                    byteHeader[0] == 0xFE &&
+                    byteHeader[1] == 0xFF)
+            {
+                // UCS-2 Big Endian
+                charset = Charset.forName("UTF-16BE");
+            }
+            else if (
+                    byteHeader[0] == 0xFF &&
+                    byteHeader[1] == 0xFE)
+            {
+                // UCS-2 Little Endian
+                charset = Charset.forName("UTF-16LE");
+            }
+            else if (
+                    bytesRead >= 3 &&
+                    byteHeader[0] == 0xEF &&
+                    byteHeader[1] == 0xBB &&
+                    byteHeader[2] == 0xBF)
+            {
+                // UTF-8
+                charset = Charset.forName("UTF-8");
+            }
+            else
+            {
+                // No idea
+                charset = null;
+            }
+            // Done
+            return charset;
+        }
+        finally
+        {
+            if (bis != null)
+            {
+                try { bis.close(); } catch (Throwable e) {}
+            }
+        }
+    }
+}