Bug #558: JDBC InputStream.read() from oid returns incorrect values for negative bytes and really messes up -1

James Lynn (JamesLynn(at)mail(dot)com) reports a bug with a severity of 2
The lower the number the more severe it is.

Short Description
JDBC InputStream.read() from oid returns incorrect values for negative bytes and really messes up -1

Long Description
Using: PostgresSQL 7.1, jdbc7.1-1.2.jar

After inserting a large object (oid) and trying to select it back out, the InputStream returns incorrect values when calling read() if the input contained any negative bytes. Example: 0xFE should return 254 but incorrectly returns -2. The worst case is when you have 0xFF in the large object: since read() returns -1 rather than 255 and -1 is the signal that you have reached the end of stream so you can never tell if you have a -1.

There is also a problem with read(byte[],int,int), where the 0xFF just doesn't appear in the data. This may or may not be related.

To set up the example you must use the following create statement:
create table x (f oid);

The example code is Bug.java.

Sample Code
import java.sql.*;
import java.io.*;
import java.util.*;

public class Bug
{
public static void main(String[] args) throws Exception
{
byte[] data={0,-2,-1,0};

// Test way
{
OutputStream out=new FileOutputStream("bug.test");
out.write(data);
out.close();

InputStream in=new FileInputStream("bug.test");
ByteArrayOutputStream baos=new ByteArrayOutputStream();
int ch;
System.out.print("Correct: ");
while ((ch=in.read())!=-1) { System.out.print(ch);System.out.print(','); baos.write(ch);}
System.out.print(ch);System.out.print(';');
System.out.println(hex(baos.toByteArray()));
}

Connection c=null;
Connection c2=null;
Class.forName("org.postgresql.Driver");
String url="jdbc:postgresql://dev002.oakscape.com/shipvis";
String username="shipvis";
String password="shipvis";
c=DriverManager.getConnection(url, username, password);
c.setAutoCommit(false);

c.prepareStatement("delete from x").execute();
c.commit();
PreparedStatement insert=c.prepareStatement("insert into x (f) values (?)");

insert.setBinaryStream(1,new ByteArrayInputStream(data),data.length);

insert.execute();
c.commit();

ResultSet rs=c.prepareStatement("select * from x").executeQuery();
rs.next();

// One way
{
InputStream in=rs.getBinaryStream("f");
ByteArrayOutputStream baos=new ByteArrayOutputStream();
int ch;
System.out.print("Incorrect: ");
while ((ch=in.read())!=-1) { System.out.print(ch);System.out.print(','); baos.write(ch);}
System.out.print(ch);System.out.print(';');
System.out.println(hex(baos.toByteArray()));
}

// Another way
{
InputStream in=rs.getBinaryStream("f");
ByteArrayOutputStream baos=new ByteArrayOutputStream();
byte[] ch=new byte[4];
int n;
System.out.print("Odd: ");
while ((n=in.read(ch,0,ch.length))!=-1) baos.write(ch,0,n);
System.out.println(hex(baos.toByteArray()));
}

// One way
{
InputStream in=rs.getBinaryStream("f");
ByteArrayOutputStream baos=new ByteArrayOutputStream();
int ch;
System.out.print("Know len: ");
for (int i=0;i<4;i++) { ch=in.read(); System.out.print(ch);System.out.print(','); baos.write(ch);}
System.out.print(';');
System.out.println(hex(baos.toByteArray()));
}

c.close();
}

static String hex(byte[] data)
{
StringBuffer sb=new StringBuffer();
for (int i=0;i<data.length;i++)
{
sb.append(hex((byte)(data[i]>>4))).append(hex(data[i]));
}
return sb.toString();
}
static char hex(byte data)
{
data&=0xF;
if (data<10) return (char)('0'+data);
return (char)('A'+data-10);
}
}

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