Add reformat target for consistent code formatting.

Signed-off-by: Victor Toni <victor.toni@gmail.com>

Author: ViToni

.clang-format

@@ -0,0 +1,61 @@
+Language: Cpp
+
+IndentWidth: 4
+ContinuationIndentWidth: 8
+
+ColumnLimit: 120
+
+AlignAfterOpenBracket: false
+
+AlignConsecutiveAssignments: true
+
+# not supported in clang-format-3.7
+# supported in clang-format-3.8 and above
+AlignConsecutiveDeclarations: true
+
+AlignTrailingComments: true 
+
+AllowAllParametersOfDeclarationOnNextLine: true
+
+AllowShortBlocksOnASingleLine: false
+AllowShortFunctionsOnASingleLine: false
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+
+# Control of individual brace wrapping cases
+# not supported in clang-format-3.7
+# supported in clang-format-3.8 and above
+BraceWrapping: {
+    AfterClass: 'true'
+    AfterControlStatement: 'false'
+    AfterEnum: 'true'
+    AfterFunction: 'true'
+    AfterNamespace: 'true'
+    AfterStruct: 'true'
+    AfterUnion: 'true'
+    BeforeCatch: 'true'
+    BeforeElse: 'false'
+    IndentBraces: 'false'
+}
+
+BreakBeforeBraces: Stroustrup
+
+IndentCaseLabels: true
+
+KeepEmptyLinesAtTheStartOfBlocks: true
+
+MaxEmptyLinesToKeep: 1
+
+# Pointer is aligned to right side
+PointerAlignment: Right
+
+# High penalty to avoid line break just after return type
+PenaltyReturnTypeOnItsOwnLine: 10000
+
+SpaceAfterCStyleCast: true
+
+SpacesInParentheses: false
+SpaceInEmptyParentheses: false
+SpaceBeforeParens: ControlStatements
+
+UseTab: Never

Makefile.am

@@ -8,3 +8,15 @@ ChangeLog:
 AUTHORS: ChangeLog
 	( echo "Authors and contributors, in alphabetical order: "; echo; \
 	sed -r "s/^Author: (.*)/\1/;t;d" $< | sort -u ) > $@
+
+if HAVE_CLANG_FORMAT
+
+.PHONY: reformat
+
+reformat:
+	@echo "Reformatting header files..."
+	@CLANG_FORMAT@ -style=file -i `find . -name "*.h"`
+	@echo "Reformatting C files..."
+	@CLANG_FORMAT@ -style=file -i `find . -name "*.c"`
+
+endif

configure.ac

@@ -5,6 +5,12 @@ AC_CONFIG_SRCDIR([src/igmpproxy.c])
 AC_CONFIG_HEADERS([config.h])
 AC_PROG_CC_C99
 
+AC_CHECK_PROGS(
+    [CLANG_FORMAT], [clang-format clang-format-4.0 clang-format-3.9],
+    [AC_MSG_ERROR([clang-format was not not found during configure.])]
+)
+AM_CONDITIONAL([HAVE_CLANG_FORMAT], [test -n "$CLANG_FORMAT"])
+
 AC_CANONICAL_HOST
 case $host_os in
 	linux*|uclinux*) os=linux;;