Add function 'find_and_replace'

CMakeLists.txt

@@ -36,6 +36,8 @@ if(BUILD_TESTING)
   ament_add_gtest(test_split test/test_split.cpp)
 
   ament_add_gtest(test_filesystem_helper test/test_filesystem_helper.cpp)
+
+  ament_add_gtest(test_find_and_replace test/test_find_and_replace.cpp)
 endif()
 
 ament_package()

include/rcpputils/find_and_replace.hpp

@@ -0,0 +1,93 @@
+// Copyright 2019 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCPPUTILS__FIND_AND_REPLACE_HPP_
+#define RCPPUTILS__FIND_AND_REPLACE_HPP_
+
+#include <memory>
+#include <string>
+
+namespace rcpputils
+{
+
+/// Find and replace all instances of a string with another string.
+/**
+ * \param[in] input The input string.
+ * \param[in] find The substring to replace.
+ * \param[in] replace The string to substitute for each occurrence of `find`.
+ * \return A copy of the input string with all instances of the string `find` replaced with the
+ *   string `replace`.
+ */
+template<
+  class CharT,
+  class Traits = std::char_traits<CharT>,
+  class Allocator = std::allocator<CharT>
+>
+std::basic_string<CharT, Traits, Allocator>
+find_and_replace(
+  const std::basic_string<CharT, Traits, Allocator> & input,
+  const std::basic_string<CharT, Traits, Allocator> & find,
+  const std::basic_string<CharT, Traits, Allocator> & replace)
+{
+  std::basic_string<CharT, Traits, Allocator> output = input;
+  const std::size_t find_len = find.length();
+  const std::size_t replace_len = replace.length();
+  if (find == replace) {
+    return output;
+  }
+  if (0u == find_len) {
+    return output;
+  }
+  std::size_t pos = output.find(find);
+  while (pos != std::basic_string<CharT, Traits, Allocator>::npos) {
+    output.replace(pos, find_len, replace);
+    pos = output.find(find, pos + replace_len);
+  }
+  return output;
+}
+
+namespace detail
+{
+template<typename CharT, std::size_t Length>
+std::basic_string<CharT>
+normalize_to_basic_string(const CharT (& char_string)[Length])
+{
+  return std::basic_string<CharT>(char_string);
+}
+
+template<typename StringLikeT>
+StringLikeT &&
+normalize_to_basic_string(StringLikeT && string_like)
+{
+  return string_like;
+}
+}  // namespace detail
+
+template<typename InputT, typename FindT, typename ReplaceT>
+auto
+find_and_replace(
+  InputT && input,
+  FindT && find,
+  ReplaceT && replace)
+{
+  auto input_str = detail::normalize_to_basic_string(input);
+  return find_and_replace<typename decltype(input_str)::value_type>(
+    input_str,
+    detail::normalize_to_basic_string(find),
+    detail::normalize_to_basic_string(replace));
+}
+
+}  // namespace rcpputils
+
+#endif  // RCPPUTILS__FIND_AND_REPLACE_HPP_

test/test_find_and_replace.cpp

@@ -0,0 +1,90 @@
+// Copyright 2019 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <gtest/gtest.h>
+#include <iostream>
+
+#include "rcpputils/find_and_replace.hpp"
+
+TEST(test_find_and_replace, find_and_replace) {
+  // Empty input
+  {
+    auto ret = rcpputils::find_and_replace("", "foo", "bar");
+    EXPECT_EQ("", ret);
+  }
+  // Empty find
+  {
+    auto ret = rcpputils::find_and_replace("foo", "", "bar");
+    EXPECT_EQ("foo", ret);
+  }
+  // Empty replace
+  {
+    auto ret = rcpputils::find_and_replace("foo", "foo", "");
+    EXPECT_EQ("", ret);
+  }
+  // Single occurrence
+  {
+    auto ret = rcpputils::find_and_replace("foo", "foo", "bar");
+    EXPECT_EQ("bar", ret);
+  }
+  // No occurrences
+  {
+    auto ret = rcpputils::find_and_replace("foo", "bar", "baz");
+    EXPECT_EQ("foo", ret);
+  }
+  // Multiple occurrences
+  {
+    auto ret = rcpputils::find_and_replace("foobarfoobar", "foo", "baz");
+    EXPECT_EQ("bazbarbazbar", ret);
+  }
+  {
+    auto ret = rcpputils::find_and_replace("foofoobar", "foo", "baz");
+    EXPECT_EQ("bazbazbar", ret);
+  }
+  // find == replace
+  {
+    auto ret = rcpputils::find_and_replace("foobar", "foo", "foo");
+    EXPECT_EQ("foobar", ret);
+  }
+  // find is a substring of replace
+  {
+    auto ret = rcpputils::find_and_replace("foobar", "foo", "barfoo");
+    EXPECT_EQ("barfoobar", ret);
+  }
+  // replace is a substring of find
+  {
+    auto ret = rcpputils::find_and_replace("foobar", "foobar", "bar");
+    EXPECT_EQ("bar", ret);
+  }
+}
+
+TEST(test_find_and_replace, find_and_replace_wstring) {
+  auto ret = rcpputils::find_and_replace(
+    std::wstring(L"foobar"),
+    std::wstring(L"foo"),
+    std::wstring(L"bar"));
+  EXPECT_EQ(std::wstring(L"barbar"), ret);
+}
+
+TEST(test_find_and_replace, find_and_replace_various_input_types) {
+  rcpputils::find_and_replace(std::string("foo"), "foo", "bar");
+  rcpputils::find_and_replace(std::string("foo"), std::string("foo"), "bar");
+  rcpputils::find_and_replace(std::string("foo"), "foo", std::string("bar"));
+  rcpputils::find_and_replace(std::string("foo"), std::string("foo"), std::string("bar"));
+
+  rcpputils::find_and_replace("foo", std::string("foo"), "bar");
+  rcpputils::find_and_replace("foo", std::string("foo"), std::string("bar"));
+
+  rcpputils::find_and_replace("foo", "foo", std::string("bar"));
+}