From a5b72f7ae69e5a28434fca02faba6f48ca0d09a1 Mon Sep 17 00:00:00 2001
From: Scott Wolchok <swolchok@fb.com>
Date: Fri, 8 Jan 2016 10:57:53 -0800
Subject: [PATCH] read benchmark: accept a filename as an argument

On my Macbook Pro, reading from standard input incurs a bunch of locking
overhead, which complicates profiling and (IMO) adds noise to
results. This adds the option to read from a file, which doesn't incur
this overhead.
---
 util/read.cpp | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/util/read.cpp b/util/read.cpp
index fabee1a..4734e88 100644
--- a/util/read.cpp
+++ b/util/read.cpp
@@ -1,3 +1,4 @@
+#include <fstream>
 #include <iostream>
 
 #include "yaml-cpp/emitterstyle.h"
@@ -25,9 +26,19 @@ class NullEventHandler : public YAML::EventHandler {
   virtual void OnMapEnd() {}
 };
 
-int main() {
-  YAML::Parser parser(std::cin);
+void run(YAML::Parser& parser) {
   NullEventHandler handler;
   parser.HandleNextDocument(handler);
+}
+
+int main(int argc, char** argv) {
+  if (argc > 1) {
+    std::ifstream in(argv[1]);
+    YAML::Parser parser(in);
+    run(parser);
+  } else {
+    YAML::Parser parser(std::cin);
+    run(parser);
+  }
   return 0;
 }