1 files changed, 156 insertions, 0 deletions
diff --git a/src/interfaces/jdbc/org/postgresql/largeobject/BlobInputStream.java b/src/interfaces/jdbc/org/postgresql/largeobject/BlobInputStream.java
new file mode 100644
index 0000000000..646ea97005
--- /dev/null
+++ b/src/interfaces/jdbc/org/postgresql/largeobject/BlobInputStream.java
@@ -0,0 +1,156 @@
+package org.postgresql.largeobject;
+
+import java.io.InputStream;
+import java.io.IOException;
+import java.sql.SQLException;
+
+/**
+ * This is an initial implementation of an InputStream from a large object.
+ * For now, the bare minimum is implemented. Later (after 7.1) we will overide
+ * the other read methods to optimise them.
+ */
+public class BlobInputStream extends InputStream {
+  /**
+   * The parent LargeObject
+   */
+  private LargeObject lo;
+
+  /**
+   * Buffer used to improve performance
+   */
+  private byte[] buffer;
+
+  /**
+   * Position within buffer
+   */
+  private int bpos;
+
+  /**
+   * The buffer size
+   */
+  private int bsize;
+
+  /**
+   * The mark position
+   */
+  private int mpos=0;
+
+  /**
+   * @param lo LargeObject to read from
+   */
+  public BlobInputStream(LargeObject lo) {
+    this(lo,1024);
+  }
+
+  /**
+   * @param lo LargeObject to read from
+   * @param bsize buffer size
+   */
+  public BlobInputStream(LargeObject lo,int bsize) {
+    this.lo=lo;
+    buffer=null;
+    bpos=0;
+    this.bsize=bsize;
+  }
+
+  /**
+   * The minimum required to implement input stream
+   */
+  public int read() throws java.io.IOException {
+    try {
+      if(buffer==null || bpos>=buffer.length) {
+        buffer=lo.read(bsize);
+        bpos=0;
+      }
+
+      // Handle EOF
+      if(bpos>=buffer.length)
+        return -1;
+
+      return (int) buffer[bpos++];
+    } catch(SQLException se) {
+      throw new IOException(se.toString());
+    }
+  }
+
+
+    /**
+     * Closes this input stream and releases any system resources associated
+     * with the stream.
+     *
+     * <p> The <code>close</code> method of <code>InputStream</code> does
+     * nothing.
+     *
+     * @exception  IOException  if an I/O error occurs.
+     */
+    public void close() throws IOException {
+      try {
+        lo.close();
+        lo=null;
+      } catch(SQLException se) {
+        throw new IOException(se.toString());
+      }
+    }
+
+    /**
+     * Marks the current position in this input stream. A subsequent call to
+     * the <code>reset</code> method repositions this stream at the last marked
+     * position so that subsequent reads re-read the same bytes.
+     *
+     * <p> The <code>readlimit</code> arguments tells this input stream to
+     * allow that many bytes to be read before the mark position gets
+     * invalidated.
+     *
+     * <p> The general contract of <code>mark</code> is that, if the method
+     * <code>markSupported</code> returns <code>true</code>, the stream somehow
+     * remembers all the bytes read after the call to <code>mark</code> and
+     * stands ready to supply those same bytes again if and whenever the method
+     * <code>reset</code> is called.  However, the stream is not required to
+     * remember any data at all if more than <code>readlimit</code> bytes are
+     * read from the stream before <code>reset</code> is called.
+     *
+     * <p> The <code>mark</code> method of <code>InputStream</code> does
+     * nothing.
+     *
+     * @param   readlimit   the maximum limit of bytes that can be read before
+     *                      the mark position becomes invalid.
+     * @see     java.io.InputStream#reset()
+     */
+    public synchronized void mark(int readlimit) {
+      try {
+        mpos=lo.tell();
+      } catch(SQLException se) {
+        //throw new IOException(se.toString());
+      }
+    }
+
+    /**
+     * Repositions this stream to the position at the time the
+     * <code>mark</code> method was last called on this input stream.
+     * NB: If mark is not called we move to the begining.
+     * @see     java.io.InputStream#mark(int)
+     * @see     java.io.IOException
+     */
+    public synchronized void reset() throws IOException {
+      try {
+        lo.seek(mpos);
+      } catch(SQLException se) {
+        throw new IOException(se.toString());
+      }
+    }
+
+    /**
+     * Tests if this input stream supports the <code>mark</code> and
+     * <code>reset</code> methods. The <code>markSupported</code> method of
+     * <code>InputStream</code> returns <code>false</code>.
+     *
+     * @return  <code>true</code> if this true type supports the mark and reset
+     *          method; <code>false</code> otherwise.
+     * @see     java.io.InputStream#mark(int)
+     * @see     java.io.InputStream#reset()
+     */
+    public boolean markSupported() {
+	return true;
+    }
+
+}
+\ No newline at end of file