perf hists: Add 'equal' method to perf_hpp_fmt struct

To easily compare format entries and make it available for all kinds of
format entries.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1453109064-1026-6-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
index 5a11bf0..71c8bb7 100644
--- a/tools/perf/ui/hist.c
+++ b/tools/perf/ui/hist.c
@@ -524,6 +524,11 @@
 	perf_hpp__format[PERF_HPP__OVERHEAD].name = "Overhead";
 }
 
+static bool fmt_equal(struct perf_hpp_fmt *a, struct perf_hpp_fmt *b)
+{
+	return a->equal && a->equal(a, b);
+}
+
 void perf_hpp__setup_output_field(void)
 {
 	struct perf_hpp_fmt *fmt;
@@ -542,7 +547,7 @@
 			struct perf_hpp_fmt *pos;
 
 			perf_hpp__for_each_format(pos) {
-				if (perf_hpp__same_sort_entry(pos, fmt))
+				if (fmt_equal(fmt, pos))
 					goto next;
 			}
 		}
@@ -571,7 +576,7 @@
 			struct perf_hpp_fmt *pos;
 
 			perf_hpp__for_each_sort_list(pos) {
-				if (perf_hpp__same_sort_entry(pos, fmt))
+				if (fmt_equal(fmt, pos))
 					goto next;
 			}
 		}