Fixes for issue 70. The test inputs tickled a case where the

non-blocking API would not make progress, searching for match
on the page boundary and repeatedly asking the application to
get another source block.

This is only a non-blocking issue, glad it's fixed.  I'll add
encode_decode_test to my test suite before another release.

1 files changed, 11 insertions, 2 deletions

diff --git a/xdelta3/xdelta3.c b/xdelta3/xdelta3.c
index 17985ae..3a0c6e8 100644
--- a/xdelta3/xdelta3.c
+++ b/xdelta3/xdelta3.c
@@ -3813,7 +3813,16 @@ xd3_encode_input (xd3_stream *stream)
                       return ret;
                     }
 
-                  stream->input_position += stream->match_fwd;
+                  /* The search has to make forward progress here
+                   * or else it can get stuck in a match-backward
+                   * (getsrcblk) then match-forward (getsrcblk),
+                   * find insufficient match length, then repeat
+                   * exactly the same search. */
+                  if (stream->match_fwd != 0) {
+                    stream->input_position += stream->match_fwd;
+                  } else {
+                    stream->input_position += 1;
+                  }
                 }
 
             case MATCH_SEARCHING:
@@ -4741,7 +4750,7 @@ xd3_smatch (xd3_stream *stream,
 
  again:
 
-  IF_DEBUG1 (DP(RINT "smatch at base=%u inp=%u cksum=%u\n", base,
+  IF_DEBUG2 (DP(RINT "smatch at base=%u inp=%u cksum=%u\n", base,
                 stream->input_position, scksum));
 
   /* For small matches, we can always go to the end-of-input because