Add missing file that should have been in previous commit.

diff --git a/prod/net/jaekl/qd/util/InputStreamWrapper.java b/prod/net/jaekl/qd/util/InputStreamWrapper.java
new file mode 100644 (file)
index 0000000..f78cf61
--- /dev/null
+++ b/prod/net/jaekl/qd/util/InputStreamWrapper.java
@@ -0,0 +1,47 @@
+// Copyright (C) 2014 Christian Jaekl
+
+// Wrap an inputstream, keeping a copy of the first few bytes that are read from it.
+// This is useful when passing an inputstream directly to the SAX parser, 
+// because we may want to do a post-mortem examination of the input being parsed
+// if parsing fails.
+
+package net.jaekl.qd.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+
+public class InputStreamWrapper extends InputStream {
+       final static int HEAD_MAX = 1024;
+       
+       InputStream m_is;       // the stream being wrapped
+       byte[] m_head;          // the first (up to HEAD_MAX) bytes that were read from the wrapped stream
+       int    m_headBytes;     // number of bytes stored in m_head
+       
+       public InputStreamWrapper(InputStream is)
+       {
+               super();
+               
+               m_is = is;
+               m_head = new byte[HEAD_MAX];
+               m_headBytes = 0;
+       }
+       
+       @Override
+       public int read() throws IOException {
+               int b = m_is.read();
+               if ((-1) == b) {
+                       // end-of-stream
+                       return b;
+               }
+               if (m_headBytes < HEAD_MAX) {
+                       m_head[m_headBytes] = (byte)b;
+                       m_headBytes++;
+               }
+               return b;
+       }
+       
+       public byte[] getHeadBytes() {
+               return Arrays.copyOf(m_head, m_headBytes);
+       }
+}