Add string Join functionality

Signed-off-by: Michael Carroll <[email protected]>
gazebosim · Oct 19, 2020 · faff823 · faff823
1 parent 0b2bd23
commit faff823
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diff --git a/include/ignition/common/StringUtils.hh b/include/ignition/common/StringUtils.hh
@@ -33,6 +33,30 @@ namespace ignition
     std::vector<std::string> IGNITION_COMMON_VISIBLE Split(
         const std::string &_orig, char _delim);
 
+    /// \brief Join a sequence of strings with a delimiter
+    ///
+    /// Note that this will skip any empty entries in the vector,
+    /// and will also not prepend or append the delimiter to the
+    /// final output string
+    ///
+    /// \param[in] _orig The input sequence of strings
+    /// \param[in] _delim a string delimiter to join the string with
+    /// \returns a single string composed of strings joined with the delimiter
+    std::string IGNITION_COMMON_VISIBLE Join(
+        const std::vector<std::string> &_orig, const std::string &_delim);
+
+    /// \brief Join a sequence of strings with a delimiter
+    ///
+    /// Note that this will skip any empty entries in the vector,
+    /// and will also not prepend or append the delimiter to the
+    /// final output string
+    ///
+    /// \param[in] _orig The input sequence of strings
+    /// \param[in] _delim a character to join the string with
+    /// \returns a single string composed of strings joined with the delimiter
+    std::string IGNITION_COMMON_VISIBLE Join(
+        const std::vector<std::string> &_orig, char _delim);
+
     /// \brief return true if string starts with another string
     /// \param[in] _s1 the string to check
     /// \param[in] _s2 the possible prefix

diff --git a/src/StringUtils.cc b/src/StringUtils.cc
@@ -38,6 +38,29 @@ namespace ignition
       return pieces;
     }
 
+    //////////////////////////////////////////////////
+    std::string Join(const std::vector<std::string> &_orig, const std::string &_delim)
+    {
+      std::string ret = "";
+      for (size_t ii = 0; ii < _orig.size(); ++ii)
+      {
+        if (_orig[ii].empty())
+          continue;
+
+        ret += _orig[ii];
+        if (ii < _orig.size() - 1)
+        {
+          ret += _delim;
+        }
+      }
+      return ret;
+    }
+    //////////////////////////////////////////////////
+    std::string Join(const std::vector<std::string> &_orig, char _delim)
+    {
+      return Join(_orig, std::string(1, _delim));
+    }
+
     //////////////////////////////////////////////////
     bool StartsWith(const std::string &_s1, const std::string &_s2)
     {

diff --git a/src/StringUtils_TEST.cc b/src/StringUtils_TEST.cc
@@ -70,6 +70,59 @@ TEST(StringUtils, SplitOneDelimiterAtEnd)
   EXPECT_EQ("", pieces[1]);
 }
 
+/////////////////////////////////////////////////
+TEST(Join, Simple)
+{
+  {
+    std::string delim = " ";
+    auto pieces = std::vector<std::string>{"Hello", "World"};
+    auto joined = common::Join(pieces, delim);
+    EXPECT_EQ("Hello World", joined);
+  }
+
+  {
+    std::string delim = "x";
+    auto pieces = std::vector<std::string>{"Hello", "World"};
+    auto joined = common::Join(pieces, delim);
+    EXPECT_EQ("HelloxWorld", joined);
+  }
+
+  {
+    std::string delim = "x";
+    auto pieces = std::vector<std::string>{
+      "foo", "bar", "baz", "bing"};
+    auto joined = common::Join(pieces, delim);
+    EXPECT_EQ("fooxbarxbazxbing", joined);
+  }
+}
+
+/////////////////////////////////////////////////
+TEST(Join, EmptyDelim)
+{
+  std::string delim = "";
+  auto pieces = std::vector<std::string>{"Hello", "World"};
+  auto joined = common::Join(pieces, delim);
+  EXPECT_EQ("HelloWorld", joined);
+}
+
+/////////////////////////////////////////////////
+TEST(Join, EmptyPart)
+{
+  std::string delim = " ";
+  auto pieces = std::vector<std::string>{"Hello", "", "World"};
+  auto joined = common::Join(pieces, delim);
+  EXPECT_EQ("Hello World", joined);
+}
+
+/////////////////////////////////////////////////
+TEST(Join, EmptyParts)
+{
+  std::string delim = "x";
+  auto pieces = std::vector<std::string>{};
+  auto joined = common::Join(pieces, delim);
+  EXPECT_EQ("", joined);
+}
+
 /////////////////////////////////////////////////
 TEST(StartsWith, NotInString)
 {