From 6cb5345cd086a29a975b7fe99490e5fd1cdb1251 Mon Sep 17 00:00:00 2001
From: Richard Berger <richard.berger@temple.edu>
Date: Thu, 11 Jun 2020 13:37:22 -0400
Subject: [PATCH] Add optimized version of count_words for default whitespace
 chars

---
 src/utils.cpp                 | 29 +++++++++++++++++++++++++++++
 src/utils.h                   | 10 +++++++++-
 unittest/utils/test_utils.cpp |  4 ++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/utils.cpp b/src/utils.cpp
index 928a84883c..86f56e7b2a 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -368,6 +368,35 @@ std::string utils::trim_comment(const std::string & line) {
    Return number of words
 ------------------------------------------------------------------------- */
 
+size_t utils::count_words(const std::string & text) {
+  size_t count = 0;
+  const char * buf = text.c_str();
+  char c = *buf;
+
+  while (c) {
+    if (c == ' ' || c == '\t' || c == '\r' ||  c == '\n' || c == '\f') {
+      c = *++buf;
+      continue;
+    };
+
+    ++count;
+    c = *++buf;
+
+    while (c) {
+      if (c == ' ' || c == '\t' || c == '\r' || c == '\n' || c == '\f') {
+        break;
+      }
+      c = *++buf;
+    }
+  }
+
+  return count;
+}
+
+/* ----------------------------------------------------------------------
+   Return number of words
+------------------------------------------------------------------------- */
+
 size_t utils::count_words(const std::string & text, const std::string & separators) {
   size_t count = 0;
   size_t start = text.find_first_not_of(separators);
diff --git a/src/utils.h b/src/utils.h
index 562293f2f3..bce9ff3e66 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -156,7 +156,15 @@ namespace LAMMPS_NS {
      * \param separators string containing characters that will be treated as whitespace
      * \return number of words found
      */
-    size_t count_words(const std::string & text, const std::string & separators = " \t\r\n\f");
+    size_t count_words(const std::string & text, const std::string & separators);
+
+    /**
+     * \brief Count words in string, ignore any whitespace matching " \t\r\n\f"
+     * \param text string that should be searched
+     * \param separators string containing characters that will be treated as whitespace
+     * \return number of words found
+     */
+    size_t count_words(const std::string & text);
 
     /**
      * \brief Count words in a single line, trim anything from '#' onward
diff --git a/unittest/utils/test_utils.cpp b/unittest/utils/test_utils.cpp
index 9830207c3e..5660c097f1 100644
--- a/unittest/utils/test_utils.cpp
+++ b/unittest/utils/test_utils.cpp
@@ -28,6 +28,10 @@ TEST(Utils, count_words) {
     ASSERT_EQ(utils::count_words("some text # comment"), 4);
 }
 
+TEST(Utils, count_words_non_default) {
+    ASSERT_EQ(utils::count_words("some text # comment", " #"), 3);
+}
+
 TEST(Utils, trim_and_count_words) {
     ASSERT_EQ(utils::trim_and_count_words("some text # comment"), 2);
 }