3 files changed, 35 insertions, 10 deletions

diff --git a/xdelta3/testing/file.h b/xdelta3/testing/file.h
index 1205bc0..d3b9d4a 100644
--- a/xdelta3/testing/file.h
+++ b/xdelta3/testing/file.h
@@ -117,6 +117,11 @@ public:
   }
 
   uint8_t* Data() const {
+    if (data_ == NULL) {
+      CHECK_EQ(0, size_); 
+      data_size_ = 1;
+      data_ = new uint8_t[1];
+    }
     return data_;
   }
 
@@ -147,8 +152,8 @@ private:
 
   friend class BlockIterator;
 
-  uint8_t *data_;
-  size_t data_size_;
+  mutable uint8_t *data_;
+  mutable size_t data_size_;
   size_t size_;
 };
 
diff --git a/xdelta3/testing/regtest.cc b/xdelta3/testing/regtest.cc
index 7da4110..8bfcf51 100644
--- a/xdelta3/testing/regtest.cc
+++ b/xdelta3/testing/regtest.cc
@@ -107,8 +107,8 @@ void InMemoryEncodeDecode(const TestOptions &options,
       ret = xd3_decode_input(&decode_stream);
     }
 
-    //DP(RINT "%s = %s\n", encoding ? "encoding" : "decoding",
-    //   xd3_strerror(ret));
+    DP(RINT "%s = %s\n", encoding ? "encoding" : "decoding",
+       xd3_strerror(ret));
 
     switch (ret) {
     case XD3_OUTPUT:
@@ -146,11 +146,15 @@ void InMemoryEncodeDecode(const TestOptions &options,
 
     case XD3_INPUT:
       if (!encoding) {
+        if (target_block.Size() < target_iterator.BlockSize()) {
+          done = true;
+          continue;
+        }
         encoding = true;
         goto process;
       } else {
         if (target_block.Size() < target_iterator.BlockSize()) {
-          done = true;
+          encoding = false;
         } else {
           target_iterator.Next();
         }
@@ -162,7 +166,7 @@ void InMemoryEncodeDecode(const TestOptions &options,
         encoding = false;
       } else {
         CHECK_EQ(0, CmpDifferentBlockBytes(decoded_block, target_block));
-        //DP(RINT "verified block %"Q"u\n", target_iterator.Blkno());
+        DP(RINT "verified block %"Q"u\n", target_iterator.Blkno());
         decoded_block.Reset();
         encoding = true;
       }
@@ -603,6 +607,21 @@ void TestNonBlockingProgress() {
   InMemoryEncodeDecode(options, spec1, spec2, NULL);
 }
 
+void TestEmptyInMemory() {
+  MTRandom rand;
+  FileSpec spec0(&rand);
+  FileSpec spec1(&rand);
+  TestOptions options;
+  Block delta;
+
+  spec0.GenerateFixedSize(0);
+  spec1.GenerateFixedSize(0);
+
+  InMemoryEncodeDecode(options, spec0, spec1, &delta);
+
+  CHECK_LT(0, delta.Size());
+}
+
 void FourWayMergeTest(const TestOptions &options,
                       const FileSpec &spec0,
                       const FileSpec &spec1,
@@ -633,7 +652,6 @@ void FourWayMergeTest(const TestOptions &options,
   };
 
   CHECK_EQ(0, xd3_main_cmdline(SIZEOF_ARRAY(argv) - 1, (char**)argv));
-  
 }
 
 void TestMergeCommand() {
@@ -708,6 +726,7 @@ int main(int argc, char **argv) {
 //   TEST(TestMoveMutator);
 //   TEST(TestOverwriteMutator);
 //   TEST(TestNonBlockingProgress);
+  TEST(TestEmptyInMemory);
   TEST(TestMergeCommand);
   return 0;
 }
diff --git a/xdelta3/testing/test.h b/xdelta3/testing/test.h
index 32b62c0..536673b 100644
--- a/xdelta3/testing/test.h
+++ b/xdelta3/testing/test.h
@@ -15,10 +15,11 @@ extern "C" {
 #define CHECK_GE(x,y) CHECK_OP(x,y,>=)
 
 #define CHECK_OP(x,y,OP) \
-do {if (!((x) OP (y))) {                               \
+  do { typeof((x) OP (y)) _x(x), _y(y); \
+       if (!(_x OP _y)) { \
   cerr << __FILE__ << ":" << __LINE__ << " Check failed: " << #x " " #OP " " #y << endl; \
-  cerr << __FILE__ << ":" << __LINE__ << " Expected: " << x << endl; \
-  cerr << __FILE__ << ":" << __LINE__ << " Actual: " << y << endl; \
+  cerr << __FILE__ << ":" << __LINE__ << " Expected: " << _x << endl; \
+  cerr << __FILE__ << ":" << __LINE__ << " Actual: " << _y << endl; \
   abort(); \
     } } while (false)