Add formatter

.clang-format

@@ -0,0 +1,6 @@
+BasedOnStyle: LLVM
+ColumnLimit: 100
+IndentWidth: 4
+TabWidth: 4
+UseTab: ForContinuationAndIndentation
+AlignTrailingComments: true

.travis.yml

@@ -1,25 +1,33 @@
 sudo: required
-dist: trusty
+dist: xenial
 
 language: cpp
 
+addons:
+  apt:
+    sources:
+    - llvm-toolchain-trusty
+    packages:
+    - clang-format-9
+
 compiler:
-    - clang
-    - gcc
+  - clang
+  - gcc
 
 env:
-  - CTEST_OUTPUT_ON_FAILURE=1 USE_GCC7=0
-  - CTEST_OUTPUT_ON_FAILURE=1 USE_GCC7=1
+  - BUILD=1 CTEST_OUTPUT_ON_FAILURE=1 USE_GCC7=0
+  - BUILD=1 CTEST_OUTPUT_ON_FAILURE=1 USE_GCC7=1
 
 matrix:
   exclude:
   - compiler: clang
     env: CTEST_OUTPUT_ON_FAILURE=1 USE_GCC7=1
+  include:
+  - env: FORMAT=1
 
 before_install:
   - sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
   - sudo apt-get update -qq
-# uncomment for ubuntu precise. not needed for >=trusty - if [ "$CXX" = "g++" ]; then sudo apt-get install -y -qq g++-4.8; export CXX="g++-4.8" CC="gcc-4.8"; else echo "yes" | sudo add-apt-repository 'deb http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu precise main'; echo "yes" | sudo add-apt-repository 'deb http://llvm.org/apt/precise/ llvm-toolchain-precise-3.6 main'; wget -O - http://llvm.org/apt/llvm-snapshot.gpg.key | sudo apt-key add -; sudo apt-get update; sudo apt-get install -qq --allow-unauthenticated llvm-3.6 llvm-3.6-dev clang-3.6 libstdc++-4.8-dev; export CXX="clang++-3.6" CC="clang-3.6"; fi
   - if [ "$USE_GCC7" = "1" ]; then sudo apt-get install -y -qq g++-7; export CXX="g++-7" CC="gcc-7"; fi
   - $CXX --version
 # install json-c
@@ -68,5 +76,11 @@ before_install:
   - sudo add-apt-repository ppa:mosquitto-dev/mosquitto-ppa -y
   - sudo apt-get update -qq
   - sudo apt-get install -qq libmosquitto-dev
+
 script:
-  - cmake . -DMETEREXEC_ROOTACCESS=OFF -DENABLE_OCR=ON -DSML_HOME=/usr/local/src/libsml/sml && make && make test
+  - if [ -n "$BUILD" ]; then cmake . -DMETEREXEC_ROOTACCESS=OFF -DENABLE_OCR=ON -DSML_HOME=/usr/local/src/libsml/sml && make && make test; fi
+  - |
+    if [ -n "$FORMAT" ]; then
+      clang-format -i include/* src/*
+      test -z "$(git status --porcelain)" || (git status; git diff; false)
+    fi