svn commit: r421073 - /incubator/abdera/java/trunk/core/src/main/java/org/apache/abdera/util/SniffingInputStream.java

[jm...@apache.org]

Author: jmsnell
Date: Tue Jul 11 18:57:41 2006
New Revision: 421073

URL: http://svn.apache.org/viewvc?rev=421073&view=rev
Log:
A character encoding sniffing inputstream implementation.
Later on this evening I'll plug this into the parser so that things just work correctly.

Added:
    incubator/abdera/java/trunk/core/src/main/java/org/apache/abdera/util/SniffingInputStream.java

Added: incubator/abdera/java/trunk/core/src/main/java/org/apache/abdera/util/SniffingInputStream.java
URL: http://svn.apache.org/viewvc/incubator/abdera/java/trunk/core/src/main/java/org/apache/abdera/util/SniffingInputStream.java?rev=421073&view=auto
==============================================================================
--- incubator/abdera/java/trunk/core/src/main/java/org/apache/abdera/util/SniffingInputStream.java (added)
+++ incubator/abdera/java/trunk/core/src/main/java/org/apache/abdera/util/SniffingInputStream.java Tue Jul 11 18:57:41 2006
@@ -0,0 +1,86 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  The ASF licenses this file to You
+* under the Apache License, Version 2.0 (the "License"); you may not
+* use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.  For additional information regarding
+* copyright in this work, please see the NOTICE file in the top level
+* directory of this distribution.
+*/
+package org.apache.abdera.util;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.PushbackInputStream;
+
+/**
+ * Will attempt to autodetect the character encoding from the stream
+ * This will preserve the BOM if it exists
+ */
+public class SniffingInputStream 
+  extends FilterInputStream {
+
+  private String encoding = null;
+  private boolean bomset = false;
+  
+  protected SniffingInputStream(InputStream in) throws IOException {
+    super(new PushbackInputStream(in,4));
+    encoding = detectEncoding(); 
+  }
+
+  public boolean isBomSet() {
+    return bomset;
+  }
+  
+  public String getEncoding() {
+    return encoding;
+  }
+  
+  private String detectEncoding() throws IOException {
+    PushbackInputStream pin = (PushbackInputStream) this.in;
+    byte[] bom = new byte[4];
+    pin.read(bom);
+    pin.unread(bom);    
+    if (bom[0] == 0x00 && bom[1] == 0x00 && bom[2] == 0xFFFFFFFE && bom[3] == 0xFFFFFFFF) {
+      bomset = true;
+      return "utf-32be";
+    } else if (bom[0] == 0xFFFFFFFF && bom[1] == 0xFFFFFFFE && bom[2] == 0x00 && bom[3] == 0x00) {
+      bomset = true;
+      return "utf-32le";
+    } else if ((bom[0] == 0xFFFFFFFE && bom[1] == 0xFFFFFFFF && bom[2] == 0x00 && bom[3] == 0x00) ||
+               (bom[0] == 0x00 && bom[1] == 0x00 && bom[2] == 0xFFFFFFFF && bom[3] == 0xFFFFFFFE)) {
+      bomset = true;
+      return null;
+    } else if (bom[0] == 0xFFFFFFFE && bom[1] == 0xFFFFFFFF) {
+      bomset = true;
+      return "utf-16be";
+    } else if (bom[0] == 0xFFFFFFFF && bom[1] == 0xFFFFFFFE) {
+      bomset = true;
+      return "utf-16le";
+    } else if (bom[0] == 0xFFFFFFEF && bom[1] == 0xFFFFFFBB && bom[2] == 0xFFFFFFBF)  {
+      bomset = true;
+      return "utf-8";
+    } else if (bom[0] == 0x00 && bom[1] == 0x00 && bom[2] == 0x00 && bom[3] == 0x3C) {
+      return "utf-32be";
+    } else if (bom[0] == 0x3C && bom[1] == 0x00 && bom[2] == 0x00 && bom[3] == 0x00) {
+      return "utf-32le";
+    } else if (bom[0] == 0x00 && bom[1] == 0x3C && bom[2] == 0x00 && bom[3] == 0x3F) {
+      return "utf-16be";
+    } else if (bom[0] == 0x3C && bom[1] == 0x00 && bom[2] == 0x3F && bom[3] == 0x00) {
+      return "utf-16le";
+    } else if (bom[0] == 0x4C && bom[1] == 0x6F && bom[2] == 0xA7 && bom[3] == 0x94) {
+      return "edbdic";
+    }
+    return null;
+  }
+  
+}