From 38f2d7f65afb1bc875f1d9fbc510a62babeac930 Mon Sep 17 00:00:00 2001
From: "matthias@arch" <matthiasqui@protonmail.com>
Date: Wed, 28 Sep 2022 15:32:23 +0200
Subject: [PATCH] Fully implemented splitStringInVector

---
 src/util/string.cpp | 30 +++++++++++++++++++++++++++++-
 src/util/string.hpp | 43 +++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/src/util/string.cpp b/src/util/string.cpp
index 6045a1a..6c576f7 100644
--- a/src/util/string.cpp
+++ b/src/util/string.cpp
@@ -1,6 +1,7 @@
 #include "string.hpp"
 
 #include <sstream>
+#include <iostream>
 
 
 namespace gz::util {
@@ -25,7 +26,34 @@ std::vector<std::string> splitStringInVector(std::string& s, char separator) {
         }
     }
     return v;
-    
 }
 
+
+template<SplitStringInVectorImplemented T>
+std::vector<T> splitStringInVector(const std::string_view& s, const std::string& separator, bool skipEmptyStrings) {
+    std::vector<T> v;
+
+    std::string::size_type posStart = 0;
+    std::string::size_type posEnd = s.find(separator, posStart);
+    while (posEnd != std::string::npos) {
+        if (!(skipEmptyStrings and posStart == posEnd)) {
+            v.emplace_back(T(s.begin() + posStart, s.begin() + posEnd));
+        }
+        posStart = posEnd + 1;
+        posEnd = s.find(separator, posStart);
+    }
+    // last element
+    if (posStart < s.size()) {
+        v.emplace_back(T(s.begin() + posStart, s.end()));
+    }
+    // if last char is separator, append empty string 
+    else if (!skipEmptyStrings and posStart == s.size()) {
+        v.emplace_back(T(s.begin(), s.begin()));
+    }
+    return v;
+}
+
+template std::vector<std::string_view> splitStringInVector<std::string_view>(const std::string_view&, const std::string&, bool);
+template std::vector<std::string> splitStringInVector<std::string>(const std::string_view&, const std::string&, bool);
+
 } // namespace gz::util
diff --git a/src/util/string.hpp b/src/util/string.hpp
index 18808d2..296c5d9 100644
--- a/src/util/string.hpp
+++ b/src/util/string.hpp
@@ -3,13 +3,33 @@
 #include <string>
 #include <vector>
 #include <unordered_map>
+#include <map>
 
 namespace gz::util {
+    template<typename T>
+    concept SplitStringInVectorImplemented = std::same_as<T, std::string_view> || std::same_as<T, std::string>;
 
     /**
-     * @todo document
+     * @brief Split a string at a separator into a vector
+     * @details
+     *  Splits a string at a separator.\n
+     *  Two templates exist, one where the vector will hold std::string_views into s 
+     *  and one where it will hold std::strings. 
+     *  Behavior:
+     *  - the elements of the returned vector will not contain the separator.
+     *  - if the separator is not in s, the vector will contain s as only element.
+     *  - empty elements will occur if:
+     *    - separator is the first char
+     *    - separator is the last char
+     *    - two or more separator appear after each other\n
+     *    You can turn this behaviour off by setting skipEmptyStrings to true
+     * @note 
+     *  The string_view variant has the advantage of being faster, however:\n
+     *  The string_views will reference the original string, so it must not be changed or destroyed
+     *  as long as the string_views are used!
      */
-    std::vector<std::string> splitStringInVector(std::string& s, char separator = ',');
+    template<SplitStringInVectorImplemented T>
+    std::vector<T> splitStringInVector(const std::string_view& s, const std::string& separator, bool skipEmptyStrings=false);
 
     /**
      * @name Map with string type as key, works with strings, string_view and char*
@@ -24,8 +44,27 @@ namespace gz::util {
         size_t operator()(std::string_view str) const   { return hash_type{}(str); }
         size_t operator()(std::string const& str) const { return hash_type{}(str); }
     };
+    /**
+     * @brief A unordered_map where you can use string_views to access elements
+     * @details
+     *  To retrieve an element using a string view, you need to do this:
+     *  @code
+     *   std::string_view sv = ...;
+     *   gz::util::unordered_string_map<T> smap = { ... };
+     *   ...
+     *   if (smap.contains(sv)) {
+     *       return smap.find(sv)->second;
+     *   }
+     *  @endcode
+     *  The at() member and [] operator do not work with the string_view.
+     */
     template<typename T>
     using unordered_string_map = std::unordered_map<std::string, T, util::string_hash, std::equal_to<>>;
+    /**
+     * @brief same as unordered_string_map, but using std::map instead of std::unordered_map
+     */
+    template<typename T>
+    using string_map = std::map<std::string, T, util::string_hash, std::equal_to<>>;
     /**
      * @}
      */