Diff xmit of ID player pools

luprex/core/cpp/animqueue.cpp

@@ -301,10 +301,13 @@ void AnimQueue::add(int64_t id, const AnimStep &step) {
 }
 
 bool AnimQueue::valid() const {
-    // Animqueue must have at least one step.
+    // Animqueue must have at least one step, and no more than 255.
     if (steps_.empty()) {
         return false;
     }
+    if (steps_.size() > 255) {
+        return false;
+    }
     // First action should be blank.
     if (steps_[0].action_ != "") {
         return false;
@@ -342,17 +345,19 @@ void AnimQueue::deserialize(StreamBuffer *sb) {
     }
 }
 
-void AnimQueue::make_patch(const AnimQueue &auth, StreamBuffer *sb) const {
+bool AnimQueue::make_patch(const AnimQueue &auth, StreamBuffer *sb) const {
     // Sanity check.
     assert(valid());
     assert(auth.valid());
 
     // Special case: if we're already a perfect match, output 0 bytes.
     if (exactly_equal(auth)) {
-        return;
+        sb->write_uint8(0);
+        return false;
     }
     
     // Write the first element.
+    sb->write_uint8(auth.steps_.size());
     const AnimStep &first = auth.steps_[0];
     int match = 0;
     while ((match < int(steps_.size())) && (!steps_[match].state_equal(first))) {
@@ -388,18 +393,19 @@ void AnimQueue::make_patch(const AnimQueue &auth, StreamBuffer *sb) const {
             }
         }
     }
+    return true;
 }
 
 void AnimQueue::apply_patch(StreamBuffer *sb) {
-    // Special case: if there are zero bytes, no patch is needed.
-    if (sb->at_eof()) {
+    int len = sb->read_uint8();
+    if (len == 0) {
         return;
     }
 
     // Decode the diff, stop at eof.
     std::deque<AnimStep> old = std::move(steps_);
     steps_.clear();
-    while (!sb->at_eof()) {
+    for (int i = 0; i < len; i++) {
         uint8_t index = sb->read_uint8();
         if (index < 255) {
             assert(index < old.size());
@@ -412,9 +418,10 @@ void AnimQueue::apply_patch(StreamBuffer *sb) {
         int size = steps_.size();
         if (size > 1) {
             steps_[size-1].echo(steps_[size-2]);
+        } else {
+            steps_[0].keep_state_only();
         }
     }
-    steps_.front().keep_state_only();
 }
 
 const AnimStep &AnimQueue::back() const {
@@ -559,7 +566,7 @@ LuaDefine(unittests_animqueue, "c") {
     aq.add(12345, stp);
 
     sb.clear();
-    aqds.make_patch(aq, &sb);
+    LuaAssert(L, aqds.make_patch(aq, &sb));
     aqds.apply_patch(&sb);
     LuaAssert(L, aqds.exactly_equal(aq));
 
@@ -570,8 +577,19 @@ LuaDefine(unittests_animqueue, "c") {
     stp.set_plane("where");
     aq.add(232, stp);
 
+    // Generate diffs, but add 4 extra bytes.
     sb.clear();
-    aqds.make_patch(aq, &sb);
+    LuaAssert(L, aqds.make_patch(aq, &sb));
+    sb.write_uint32(0);
+
+    // Apply the diffs, 4 extra bytes should remain.
+    aqds.apply_patch(&sb);
+    LuaAssert(L, sb.write_count() - sb.read_count() == 4);
+    LuaAssert(L, aqds.exactly_equal(aq));
+
+    // compare again, should be no differences.
+    sb.clear();
+    LuaAssert(L, !aqds.make_patch(aq, &sb));
     aqds.apply_patch(&sb);
     LuaAssert(L, aqds.exactly_equal(aq));
 
@@ -579,7 +597,7 @@ LuaDefine(unittests_animqueue, "c") {
     aq.keep_only(1);
 
     sb.clear();
-    aqds.make_patch(aq, &sb);
+    LuaAssert(L, aqds.make_patch(aq, &sb));
     aqds.apply_patch(&sb);
     LuaAssert(L, aqds.exactly_equal(aq));