1 files changed, 70 insertions, 0 deletions
diff --git a/core/blockpool.go b/core/blockpool.go
new file mode 100644
index 0000000..bfde881
--- /dev/null
+++ b/core/blockpool.go
@@ -0,0 +1,70 @@
+// Copyright 2018 The dexon-consensus-core Authors
+// This file is part of the dexon-consensus-core library.
+//
+// The dexon-consensus-core library is free software: you can redistribute it
+// and/or modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The dexon-consensus-core library is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the dexon-consensus-core library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package core
+
+import (
+	"container/heap"
+
+	"github.com/dexon-foundation/dexon-consensus-core/core/types"
+)
+
+// blockPool is a slice of heap of blocks, indexed by chainID,
+// and the heap is sorted based on heights of blocks.
+type blockPool []types.ByHeight
+
+// newBlockPool constructs a blockPool.
+func newBlockPool(chainNum uint32) (pool blockPool) {
+	pool = make(blockPool, chainNum)
+	for _, p := range pool {
+		heap.Init(&p)
+	}
+	return
+}
+
+// addBlock adds a block into pending set and make sure these
+// blocks are sorted by height.
+func (p blockPool) addBlock(b *types.Block) {
+	heap.Push(&p[b.Position.ChainID], b)
+}
+
+// purgeBlocks purge blocks of that chain with less-or-equal height.
+// NOTE: we won't check the validity of 'chainID', the caller should
+//       be sure what he is expecting.
+func (p blockPool) purgeBlocks(chainID uint32, height uint64) {
+	for {
+		if len(p[chainID]) == 0 || p[chainID][0].Position.Height > height {
+			break
+		}
+		heap.Pop(&p[chainID])
+	}
+}
+
+// tip get the blocks with lowest height of the chain if any.
+func (p blockPool) tip(chainID uint32) *types.Block {
+	if len(p[chainID]) == 0 {
+		return nil
+	}
+	return p[chainID][0]
+}
+
+// removeTip removes block with lowest height of the specified chain.
+func (p blockPool) removeTip(chainID uint32) {
+	if len(p[chainID]) > 0 {
+		heap.Pop(&p[chainID])
+	}
+}