Initial commit: SRDB - High-performance LSM-Tree database

- Core engine with MemTable, SST, WAL
- B+Tree indexing for SST files  
- Leveled compaction strategy
- Multi-table database management
- Schema validation and secondary indexes
- Query builder with complex conditions
- Web UI with HTMX for data visualization
- Command-line tools for diagnostics

btree/btree_test.go

@@ -0,0 +1,155 @@
+package btree
+
+import (
+	"os"
+	"testing"
+
+	"github.com/edsrzf/mmap-go"
+)
+
+func TestBTree(t *testing.T) {
+	// 1. 创建测试文件
+	file, err := os.Create("test.sst")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove("test.sst")
+
+	// 2. 构建 B+Tree
+	builder := NewBuilder(file, 256) // 从 offset 256 开始
+
+	// 添加 1000 个 key-value
+	for i := int64(1); i <= 1000; i++ {
+		dataOffset := 1000000 + i*100 // 模拟数据位置
+		dataSize := int32(100)
+		err := builder.Add(i, dataOffset, dataSize)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	// 构建
+	rootOffset, err := builder.Build()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Logf("Root offset: %d", rootOffset)
+
+	// 3. 关闭并重新打开文件
+	file.Close()
+
+	file, err = os.Open("test.sst")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file.Close()
+
+	// 4. mmap 映射
+	mmapData, err := mmap.Map(file, mmap.RDONLY, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer mmapData.Unmap()
+
+	// 5. 查询测试
+	reader := NewReader(mmapData, rootOffset)
+
+	// 测试存在的 key
+	for i := int64(1); i <= 1000; i++ {
+		offset, size, found := reader.Get(i)
+		if !found {
+			t.Errorf("Key %d not found", i)
+		}
+		expectedOffset := 1000000 + i*100
+		if offset != expectedOffset {
+			t.Errorf("Key %d: expected offset %d, got %d", i, expectedOffset, offset)
+		}
+		if size != 100 {
+			t.Errorf("Key %d: expected size 100, got %d", i, size)
+		}
+	}
+
+	// 测试不存在的 key
+	_, _, found := reader.Get(1001)
+	if found {
+		t.Error("Key 1001 should not exist")
+	}
+
+	_, _, found = reader.Get(0)
+	if found {
+		t.Error("Key 0 should not exist")
+	}
+
+	t.Log("All tests passed!")
+}
+
+func TestBTreeSerialization(t *testing.T) {
+	// 测试节点序列化
+	leaf := NewLeafNode()
+	leaf.AddData(1, 1000, 100)
+	leaf.AddData(2, 2000, 200)
+	leaf.AddData(3, 3000, 300)
+
+	// 序列化
+	data := leaf.Marshal()
+	if len(data) != NodeSize {
+		t.Errorf("Expected size %d, got %d", NodeSize, len(data))
+	}
+
+	// 反序列化
+	leaf2 := Unmarshal(data)
+	if leaf2 == nil {
+		t.Fatal("Unmarshal failed")
+	}
+
+	// 验证
+	if leaf2.NodeType != NodeTypeLeaf {
+		t.Error("Wrong node type")
+	}
+	if leaf2.KeyCount != 3 {
+		t.Errorf("Expected 3 keys, got %d", leaf2.KeyCount)
+	}
+	if len(leaf2.Keys) != 3 {
+		t.Errorf("Expected 3 keys, got %d", len(leaf2.Keys))
+	}
+	if leaf2.Keys[0] != 1 || leaf2.Keys[1] != 2 || leaf2.Keys[2] != 3 {
+		t.Error("Keys mismatch")
+	}
+	if leaf2.DataOffsets[0] != 1000 || leaf2.DataOffsets[1] != 2000 || leaf2.DataOffsets[2] != 3000 {
+		t.Error("Data offsets mismatch")
+	}
+	if leaf2.DataSizes[0] != 100 || leaf2.DataSizes[1] != 200 || leaf2.DataSizes[2] != 300 {
+		t.Error("Data sizes mismatch")
+	}
+
+	t.Log("Serialization test passed!")
+}
+
+func BenchmarkBTreeGet(b *testing.B) {
+	// 构建测试数据
+	file, _ := os.Create("bench.sst")
+	defer os.Remove("bench.sst")
+
+	builder := NewBuilder(file, 256)
+	for i := int64(1); i <= 100000; i++ {
+		builder.Add(i, i*100, 100)
+	}
+	rootOffset, _ := builder.Build()
+	file.Close()
+
+	// mmap
+	file, _ = os.Open("bench.sst")
+	defer file.Close()
+	mmapData, _ := mmap.Map(file, mmap.RDONLY, 0)
+	defer mmapData.Unmap()
+
+	reader := NewReader(mmapData, rootOffset)
+
+	// 性能测试
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		key := int64(i%100000 + 1)
+		reader.Get(key)
+	}
+}