add clang format

.clang-format

@@ -0,0 +1,37 @@
+Language: Cpp
+BasedOnStyle: LLVM
+
+AlignAfterOpenBracket: DontAlign
+BreakConstructorInitializers: AfterColon
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+PointerAlignment: Left
+SortIncludes: true
+SpacesBeforeTrailingComments: 2
+UseTab: Always
+MaxEmptyLinesToKeep: 5
+
+TabWidth: 4
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+IndentWidth: 4
+IndentCaseLabels: true
+
+ColumnLimit: 135
+AlwaysBreakTemplateDeclarations: Yes
+
+AllowShortFunctionsOnASingleLine: Empty
+BreakBeforeBraces: Custom
+BraceWrapping:
+  AfterClass: false
+  AfterControlStatement: false
+  AfterEnum: false
+  AfterExternBlock: false
+  AfterFunction: false
+  AfterNamespace: false
+  AfterStruct: false
+  AfterUnion: false
+  BeforeCatch: false
+  BeforeElse: false
+  IndentBraces: false
+  SplitEmptyFunction: true
+  SplitEmptyRecord: true