Thread: [PATCHES] BlobInputStream.java patch

The current implementation of BlobInputStream does
not properly handle 8-bit unsigned data as it blindly
casts the byte to an int, which java most helpfully
promotes to a signed type.  This causes problems when
you can only return -1 to indicated EOF.

The following patch fixes the bug and has been tested
locally on image data.

Chad David
Guild Software Inc.
davidc@guild.ab.ca


*** BlobInputStream.java    Thu Feb 22 11:11:23 2001
--- BlobInputStream.patched Thu Feb 22 11:10:38 2001
***************
*** 58,73 ****
     */
    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());
      }
--- 58,81 ----
     */
    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;
+       }

!       int ret = (buffer[bpos] & 0x7F);
!       if ((buffer[bpos] &0x80) == 0x80) {
!         ret |= 0x80;
!       }
!
!       bpos++;
!
!       return ret;
      } catch(SQLException se) {
        throw new IOException(se.toString());
      }
***************
*** 153,156 ****
    return true;
      }

! }
--- 161,164 ----
    return true;
      }

! }