CMakeLists.txt

@@ -32,6 +32,7 @@ endif()
 target_sources(
   ${PROJECT_NAME}
   PRIVATE 3party/mongoose/mongoose.c
+          src/ulib/utils/utils.cpp
           src/ulib/base/location.h
           src/ulib/base/location.cpp
           src/ulib/status.h

src/ulib/utils/utils.cpp

@@ -0,0 +1,29 @@
+#include "utils.h"
+#include <sstream>
+
+namespace ulib {
+std::string
+StrJoin(std::vector<nonstd::string_view> &vec,
+        nonstd::string_view delimiter,
+        bool ignore_empty_str)
+{
+    if (vec.empty()) { return ""; }
+
+    auto iter = vec.cbegin();
+    if (ignore_empty_str) {
+        // find first non-empty string
+        while (iter != vec.cend() && iter->empty()) { ++iter; }
+    }
+
+    if (iter == vec.cend()) { return ""; }
+    std::stringstream ss;
+    ss << *iter;
+    for (++iter; iter != vec.cend(); ++iter) {
+        if (ignore_empty_str && iter->empty()) { continue; }
+        ss << delimiter << *iter;
+    }
+
+    return std::move(ss.str());
+}
+
+}// namespace ulib

src/ulib/utils/utils.h

@@ -2,8 +2,18 @@
 #define ULIB_SRC_ULIB_UTILS_UTILS_H_
 
 #include <functional>
+#include <string_view.hpp>
+#include <type_traits>
+#include <vector>
 
 namespace ulib {
+template<typename T, class Comp>
+const T &
+Clamp(const T &value, const T &low, const T &high, Comp comp)
+{
+    return comp(value, low) ? low : (comp(high, value) ? high : value);
+}
+
 template<typename T>
 const T &
 Clamp(const T &value, const T &low, const T &high)
@@ -11,12 +21,9 @@ Clamp(const T &value, const T &low, const T &high)
     return Clamp(value, low, high, std::less<T>{});
 }
 
-template<typename T, typename Comp>
+std::string StrJoin(std::vector<nonstd::string_view> &vec,
-const T &
+                    nonstd::string_view delimiter = ",",
-Clamp(const T &value, const T &low, const T &high, Comp comp)
+                    bool ignore_empty_str = true);
-{
-    return comp(value, low) ? low : (comp(high, value) ? high : value);
-}
 
 }// namespace ulib
 #endif//  ULIB_SRC_ULIB_UTILS_UTILS_H_

tests/CMakeLists.txt

@@ -17,6 +17,7 @@ add_executable(
   3party/optional/optional_unittest.cpp
   3party/sqlpp11/sqlpp11_unittest.cpp
   ulib/utils/defer_unittest.cpp
+  ulib/utils/utils_unittest.cpp
   ulib/status_or_unittest.cpp)
 target_link_libraries(ulib_test PRIVATE ulib gtest gtest_main)
 

tests/ulib/utils/utils_unittest.cpp

@@ -0,0 +1,34 @@
+#include <gtest/gtest.h>
+#include <ulib/utils/utils.h>
+
+TEST(Utils, Clamp)
+{
+    EXPECT_EQ(ulib::Clamp(1, 2, 3), 2);
+    EXPECT_EQ(ulib::Clamp(2, 2, 3), 2);
+    EXPECT_EQ(ulib::Clamp(3, 2, 3), 3);
+    EXPECT_EQ(ulib::Clamp(4, 2, 3), 3);
+}
+
+TEST(Utils, StrJoin)
+{
+    std::vector<nonstd::string_view> vec{"a", "b", "c"};
+    EXPECT_EQ(ulib::StrJoin(vec, ","), "a,b,c");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", false), "a,b,c");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", true), "a,b,c");
+    vec = {"a", "", "c"};
+    EXPECT_EQ(ulib::StrJoin(vec, ","), "a,c");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", false), "a,,c");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", true), "a,c");
+    vec = {"", "", ""};
+    EXPECT_EQ(ulib::StrJoin(vec, ","), "");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", false), ",,");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", true), "");
+    vec = {"a", "b", ""};
+    EXPECT_EQ(ulib::StrJoin(vec, ","), "a,b");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", false), "a,b,");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", true), "a,b");
+    vec = {"", "b", "c"};
+    EXPECT_EQ(ulib::StrJoin(vec, ","), "b,c");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", false), ",b,c");
+    EXPECT_EQ(ulib::StrJoin(vec, ",", true), "b,c");
+}