Add clang-formatting to Jenkins

This commit adds a clang-format file to the repository, and scripts
that will call the formatter on Jenkins to make sure that merge requests
are formatted correctly. There is a corresponding jenkins change to make
this happen automatically.

The clang-format version is unspecified by default, to match the unadorned
clang-format that comes with LLVM's binary archives. You can still specify
it when using it with the git hooks if you want to use it locally, say with
'clang-format-3.9', if that is what your package manager has called it.

One minor update has been made to the format file: instead of
inferring where * and & bind to, they are now specified to be on the
left.  Allowing it to be guessed by clang-format means that the style
was inconsistent across the repo's files. It is otherwise the same as
Google style from clang-format-3.9. The repository has been formatted
to match this style in this commit as well. From now on, there should
be no noisy format commits, ideally.

.clang-format

@@ -0,0 +1,89 @@
+---
+Language:        Cpp
+# BasedOnStyle:  Google
+AccessModifierOffset: -1
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+AlignEscapedNewlinesLeft: true
+AlignOperands:   true
+AlignTrailingComments: true
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: All
+AllowShortIfStatementsOnASingleLine: true
+AllowShortLoopsOnASingleLine: true
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: true
+AlwaysBreakTemplateDeclarations: true
+BinPackArguments: true
+BinPackParameters: true
+BraceWrapping:
+  AfterClass:      false
+  AfterControlStatement: false
+  AfterEnum:       false
+  AfterFunction:   false
+  AfterNamespace:  false
+  AfterObjCDeclaration: false
+  AfterStruct:     false
+  AfterUnion:      false
+  BeforeCatch:     false
+  BeforeElse:      false
+  IndentBraces:    false
+BreakBeforeBinaryOperators: None
+BreakBeforeBraces: Attach
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializersBeforeComma: false
+BreakStringLiterals: true
+ColumnLimit:     80
+CommentPragmas:  '^ IWYU pragma:'
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat:   false
+ExperimentalAutoDetectBinPacking: false
+ForEachMacros:   [ foreach, Q_FOREACH, BOOST_FOREACH ]
+IncludeCategories:
+  - Regex:           '^<.*\.h>'
+    Priority:        1
+  - Regex:           '^<.*'
+    Priority:        2
+  - Regex:           '.*'
+    Priority:        3
+IncludeIsMainRegex: '([-_](test|unittest))?$'
+IndentCaseLabels: true
+IndentWidth:     2
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: false
+MacroBlockBegin: ''
+MacroBlockEnd:   ''
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+PenaltyBreakBeforeFirstCallParameter: 1
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakString: 1000
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 200
+PointerAlignment: Left
+ReflowComments:  true
+SortIncludes:    true
+SpaceAfterCStyleCast: false
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 2
+SpacesInAngles:  false
+SpacesInContainerLiterals: true
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+Standard:        Auto
+TabWidth:        8
+UseTab:          Never
+...
+

hooks/clang-format-all.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+set -euo pipefail
+IFS=$'\n\t'
+
+VERSION=''
+
+git ls-files | grep -E "*\.h$|*\.hpp$|*\.cc$|*\.cpp$" | \
+  xargs clang-format$VERSION -style=file -i

hooks/is-clang-formatted.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+set -euo pipefail
+IFS=$'\n\t'
+
+hooks/clang-format-all.sh
+git diff --quiet

test/helpers/fast_div.cc

@@ -65,19 +65,19 @@ TYPED_TEST(FastDivTest, DivideBy12) {
 }
 TYPED_TEST(FastDivTest, AllValuesDivisorsLessThan10) {
   TypeParam max = 1024;
-  for(TypeParam div = 2; div < 10; ++div) {
+  for (TypeParam div = 2; div < 10; ++div) {
     this->check_all_values_up_to(max, div);
   }
 }
 TYPED_TEST(FastDivTest, AllValuesDivisors10To20) {
   TypeParam max = 1024;
-  for(TypeParam div = 10; div < 20; ++div) {
+  for (TypeParam div = 10; div < 20; ++div) {
     this->check_all_values_up_to(max, div);
   }
 }
 TYPED_TEST(FastDivTest, AllValuesDivisors100To200) {
   TypeParam max = 1024;
-  for(TypeParam div = 100; div < 200; ++div) {
+  for (TypeParam div = 100; div < 200; ++div) {
     this->check_all_values_up_to(max, div);
   }
 }

test/helpers/output_window_index.cc

@@ -20,9 +20,9 @@
 template <typename T>
 struct IndexHelpersOutWindow : public ::testing::Test {
   void check_output_window(T const stride, T const pad,
-                          std::vector<T> const& index,
-                          std::vector<T> const& exp_win,
-                          std::vector<T> const& exp_fil) {
+                           std::vector<T> const& index,
+                           std::vector<T> const& exp_win,
+                           std::vector<T> const& exp_fil) {
     ASSERT_EQ(index.size(), exp_win.size());
     ASSERT_EQ(index.size(), exp_fil.size());
     for (size_t i = 0; i < index.size(); ++i) {