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Input/Output of byte[]-Fields with 'FF' values in LargeObject with JDBC

From: pgsql-bugs(at)postgresql(dot)org
To: pgsql-bugs(at)postgresql(dot)org
Subject: Input/Output of byte[]-Fields with 'FF' values in LargeObject with JDBC
Date: 2001-04-27 11:29:33
Message-ID: 200104271129.f3RBTXs36182@hub.org (view raw or flat)
Thread:
Lists: pgsql-bugs
wolfgang (w(dot)hickl(at)gis-systemhaus(dot)de) reports a bug with a severity of 2
The lower the number the more severe it is.

Short Description
Input/Output of byte[]-Fields with 'FF' values in LargeObject with JDBC

Long Description
The following Java-Code don't work because of the "0xff" values
in the byteField:

                byte[] byteField = new byte[6];
                byteField[0] = (new Integer(0xff).byteValue());
                byteField[1] = (new Integer(0xff).byteValue());
                byteField[2] = (new Integer(0x00).byteValue());
                byteField[3] = (new Integer(0x02).byteValue());
                byteField[4] = (new Integer(0x53).byteValue());


                ByteArrayInputStream byteStream = 
                    new ByteArrayInputStream(byteField);
                
                      psta.setBinaryStream(blobIdx,byteStream,byteField.length);

My changes in the JDBC-Driver to fix this problem:

=> Change in org.postgresql.jdbc2.PreparedStatement



	public void setBinaryStream(int parameterIndex, InputStream x, int length) throws SQLException
	{
          LargeObjectManager lom = connection.getLargeObjectAPI();
          int oid = lom.create();
          LargeObject lob = lom.open(oid);
          OutputStream los = lob.getOutputStream();
          try {
            // could be buffered, but then the OutputStream returned by LargeObject
            // is buffered internally anyhow, so there would be no performance
            // boost gained, if anything it would be worse!
            int c=x.read();
            int p=0;
// !!! the value of a byte don't care => while(c>-1 && p<length) {
            while(p<length)   
            {
              los.write(c);
              c=x.read();
              p++;
            }
            los.close();
          } catch(IOException se) {
            throw new PSQLException("postgresql.prep.is",se);
          }
          // lob is closed by the stream so don't call lob.close()
          setInt(parameterIndex,oid);
	}


=> New Method in org.postgresql.largeobject.BlobInputStream;


    /**
     * Read in Byte[]
     */
    public int read(byte[] aByteArray) throws java.io.IOException
    {

        try {
            byte buf[] = lo.read(aByteArray.length);
            
            for (int ii=0; ii < buf.length; ii++)
            {
                aByteArray[ii] = buf[ii];
            }
            return(buf.length);
        }
        catch(SQLException se)
        {
            throw new IOException(se.toString());
        }

    } // ende read(byte[])


Best regards
Wolfgang


Sample Code


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