4 files changed, 28 insertions, 11 deletions

diff --git a/xdelta3/testing/regtest.cc b/xdelta3/testing/regtest.cc
index f0b7a42..7a9884d 100644
--- a/xdelta3/testing/regtest.cc
+++ b/xdelta3/testing/regtest.cc
@@ -825,6 +825,7 @@ void TestMergeCommand2() {
 
 #define TEST(x) cerr << #x << "..." << endl; regtest.x()
 
+// These tests are primarily tests of the testing framework itself.
 template <class T>
 void UnitTest() {
   Regtest<T> regtest;
@@ -839,6 +840,7 @@ void UnitTest() {
   TEST(TestOverwriteMutator);
 }
 
+// These are Xdelta tests.
 template <class T>
 void MainTest() {
   Regtest<T> regtest;
@@ -852,6 +854,7 @@ void MainTest() {
 
 #undef TEST
 
+// Run the unittests, followed by xdelta tests for various constants.
 int main(int argc, char **argv) {
   UnitTest<SmallBlock>();
   MainTest<SmallBlock>();
diff --git a/xdelta3/testing/xdelta3-regtest.py b/xdelta3/testing/xdelta3-regtest.py
index 94f527e..d0a602f 100755
--- a/xdelta3/testing/xdelta3-regtest.py
+++ b/xdelta3/testing/xdelta3-regtest.py
@@ -31,7 +31,7 @@ import xdelta3
 
 #RCSDIR = '/Users/jmacd/src/ftp.kernel.org/pub/scm/linux/kernel/bkcvs/linux-2.4/net/x25'
 #RCSDIR = '/Users/jmacd/src/ftp.kernel.org/pub/scm/linux/kernel/bkcvs/linux-2.4/fs'
-RCSDIR = '/Users/jmacd/src/kernel.org'
+RCSDIR = '/Users/jmacd/src/ftp.kernel.org'
 
 #
 MIN_SIZE       = 0
diff --git a/xdelta3/xdelta3.c b/xdelta3/xdelta3.c
index 6d014aa..20bffdb 100644
--- a/xdelta3/xdelta3.c
+++ b/xdelta3/xdelta3.c
@@ -2513,7 +2513,7 @@ usize_t xd3_bytes_on_srcblk (xd3_source *src, xoff_t blkno)
 }
 
 /* This function interfaces with the client getblk function, checks
- * its results, updates frontier_blkno, max_blkno, onlastblk. */
+ * its results, updates frontier_blkno, max_blkno, onlastblk, eof_known. */
 static int
 xd3_getblk (xd3_stream *stream, xoff_t blkno)
 {
@@ -2547,7 +2547,8 @@ xd3_getblk (xd3_stream *stream, xoff_t blkno)
         {
           source->frontier_blkno = blkno + 1;
 
-          IF_DEBUG2 (DP(RINT "[getblk] full source blkno %"Q"u: source length unknown %"Q"u\n",
+          IF_DEBUG2 (DP(RINT "[getblk] full source blkno %"Q"u: "
+                        "source length unknown %"Q"u\n",
                         blkno,
                         xd3_source_eof (source)));
         }
@@ -2555,7 +2556,8 @@ xd3_getblk (xd3_stream *stream, xoff_t blkno)
         {
           if (!source->eof_known)
             {
-              IF_DEBUG2 (DP(RINT "[getblk] eof block has %d bytes; source length known %"Q"u\n",
+              IF_DEBUG2 (DP(RINT "[getblk] eof block has %d bytes; "
+                            "source length known %"Q"u\n",
                             xd3_bytes_on_srcblk (source, blkno),
                             xd3_source_eof (source)));
               source->eof_known = 1;
@@ -4364,9 +4366,14 @@ xd3_source_match_setup (xd3_stream *stream, xoff_t srcpos)
     }
 
   /* Implement srcwin_maxsz, which prevents the encoder from seeking
-   * back further than the LRU cache maintaining FIFO discipline,
-   * which causes terrible performance. */
-  frontier_pos = stream->src->frontier_blkno * stream->src->blksize;
+   * back further than the LRU cache maintaining FIFO discipline, (to
+   * avoid seeking). */
+  frontier_pos = stream->src->eof_known ?
+    xd3_source_eof (stream->src) :
+    (stream->src->frontier_blkno * stream->src->blksize);
+  IF_DEBUG1(DP(RINT "[match_setup] frontier_pos %"Q"u, srcpos %"Q"u, "
+               "srcwin_maxsz %u\n",
+               frontier_pos, srcpos, stream->srcwin_maxsz));
   XD3_ASSERT (frontier_pos >= srcpos);
   if (frontier_pos - srcpos > stream->srcwin_maxsz) {
     IF_DEBUG1(DP(RINT "[match_setup] rejected due to srcwin_maxsz "
diff --git a/xdelta3/xdelta3.h b/xdelta3/xdelta3.h
index f417dcf..c831ac1 100644
--- a/xdelta3/xdelta3.h
+++ b/xdelta3/xdelta3.h
@@ -752,10 +752,17 @@ struct _xd3_source
   xoff_t              getblkno;      /* request block number: xd3 sets
                                         current getblk request */
 
-  xoff_t              max_blkno;
-  xoff_t              frontier_blkno;
-  usize_t             onlastblk;
-  int                 eof_known;
+  /* See xd3_getblk() */
+  xoff_t              max_blkno;  /* Maximum block, if eof is known,
+                                   * otherwise, equals frontier_blkno
+                                   * (initially 0). */
+  xoff_t              frontier_blkno;  /* If eof is unknown, the next
+                                        * source position to be read.
+                                        * Otherwise, equal to
+                                        * max_blkno. */
+  usize_t             onlastblk;  /* Number of bytes on max_blkno */
+  int                 eof_known;  /* Set to true when the first
+                                   * partial block is read. */
 };
 
 /* The primary xd3_stream object, used for encoding and decoding.  You