stdutils: Additions to string.h

- Add string::Indent.
- Remove some old code from string.h
    Use C++17's library header <filesystem> for this kind of
    filename manipulations.
- Freshen up: tolower, toupper and capitalize.

src/stdutils/include/stdutils/string.h

@@ -2,6 +2,7 @@
 // This code is distributed under the terms of the MIT License
 #pragma once
 
+#include <ostream>
 #include <string>
 #include <string_view>
 
@@ -13,13 +14,55 @@ namespace string
 
 std::string tolower(const std::string& in);
 
+std::string toupper(const std::string& in);
+
 std::string capitalize(const std::string& in);
 
-std::string file_extension(std::string_view filepath);
+/**
+ * Indent: Utility class to easily output indentation to a stream
+ *
+ * Example usage:
+ *
+ *      const Indent indent(4);     // My indentation is 4 spaces
+ *
+ *      out << indent;              // Output 1 indentation
+ *      out << indent(2);           // Output 2 indentations
+ */
+template <typename CharT>
+class BasicIndent : private std::basic_string<CharT>
+{
+public:
+    class Multi;
+
+    BasicIndent(std::size_t count, CharT ch = ' ') : std::basic_string<CharT>(count, ch) {}
+
+    Multi operator()(std::size_t factor) const { return Multi(*this, factor); }
+
+    friend std::basic_ostream<CharT>& operator<<(std::basic_ostream<CharT>& out, const BasicIndent<CharT>& indent)
+    {
+        return out << static_cast<const std::basic_string<CharT>&>(indent);
+    }
+};
+
+template <typename CharT>
+class BasicIndent<CharT>::Multi
+{
+public:
+    Multi(const BasicIndent& indent, std::size_t factor) : m_indent(indent), m_factor(factor) {}
 
-std::string filename(std::string_view filepath);
+    // NB: Read https://isocpp.org/wiki/faq/templates#template-friends regarding templated friend functions
+    friend std::basic_ostream<CharT>& operator<<(std::basic_ostream<CharT>& out, const Multi& multi_indent)
+    {
+        for (auto c = 0u; c < multi_indent.m_factor; c++)
+            out << multi_indent.m_indent;
+        return out;
+    }
+private:
+    const BasicIndent<CharT>& m_indent;
+    std::size_t m_factor;
+};
 
-std::string filename_wo_extension(std::string_view filepath);
+using Indent = BasicIndent<char>;
 
 } // namespace string
 } // namespace stdutils

src/stdutils/src/string.cpp

@@ -14,45 +14,24 @@ namespace string
 std::string tolower(const std::string& in)
 {
     std::string out(in);
-    std::transform(in.cbegin(), in.cend(), out.begin(), [](const char& c) { return static_cast<char>(std::tolower(c)); });
+    // Conversion from char to unsigned char is important. See STL doc.
+    std::transform(in.cbegin(), in.cend(), out.begin(), [](const unsigned char c) { return static_cast<char>(std::tolower(c)); });
     return out;
 }
 
-std::string capitalize(const std::string& in)
+std::string toupper(const std::string& in)
 {
-    std::string out = tolower(in);
-    if (!out.empty())
-        out.front() = static_cast<char>(std::toupper(out.front()));
+    std::string out(in);
+    // Conversion from char to unsigned char is important. See STL doc.
+    std::transform(in.cbegin(), in.cend(), out.begin(), [](const unsigned char c) { return static_cast<char>(std::toupper(c)); });
     return out;
 }
 
-std::string file_extension(std::string_view filepath)
-{
- std::string result(filepath);
-    const auto pos = filepath.find_last_of('.');
-    if (pos != std::string::npos)
-        return result.substr(pos + 1);
-    else
-        return "";
-}
-
-std::string filename(std::string_view filepath)
-{
-    std::string_view result(filepath);
-    const auto pos = filepath.find_last_of("/\\");
-    if (pos != std::string::npos)
-        result = filepath.substr(pos + 1);
-    return std::string(result);
-}
-
-std::string filename_wo_extension(std::string_view filepath)
+std::string capitalize(const std::string& in)
 {
-    const std::string name = filename(filepath);
-    const auto pos = name.find_last_of('.');
-    if (pos != std::string::npos)
-        return name.substr(0, pos);
-    else
-        return name;
+    std::string out = tolower(in);
+    if (!out.empty()) {  out.front() = static_cast<char>(std::toupper(static_cast<unsigned char>(out.front()))); }
+    return out;
 }
 
 } // namespace string

src/tests/stdutils/CMakeLists.txt

@@ -6,6 +6,7 @@ include(catch2)
 set(UTESTS_SOURCES
     src/test_io.cpp
     src/test_span.cpp
+    src/test_string.cpp
 )
 
 file(GLOB UTESTS_HEADERS src/*.h)

src/tests/stdutils/src/test_string.cpp

@@ -0,0 +1,35 @@
+// Copyright (c) 2023 Pierre DEJOUE
+// This code is distributed under the terms of the MIT License
+#include <catch_amalgamated.hpp>
+
+#include <stdutils/string.h>
+
+#include <sstream>
+#include <string>
+
+TEST_CASE("strings tolower, toupper and capitalize", "[stdutils::string]")
+{
+    CHECK(stdutils::string::tolower("All Those MOMENTS")  == "all those moments");
+    CHECK(stdutils::string::toupper("will be lost in time") == "WILL BE LOST IN TIME");
+    CHECK(stdutils::string::capitalize("like tears in rain.") == "Like tears in rain.");
+}
+
+TEST_CASE("Indentation", "[stdutils::string]")
+{
+    const stdutils::string::Indent indent(4);       // My indentation is 4 spaces
+    {
+        std::stringstream out;
+        out << indent;                              // Output 1 indentation
+        CHECK(out.str().size() == 4);
+    }
+    {
+        std::stringstream out;
+        out << indent(2);                           // Output 2 indentations
+        CHECK(out.str().size() == 8);
+    }
+    {
+        std::stringstream out;
+        out << indent(0);                           // Output zero indentation
+        CHECK(out.str().empty());
+    }
+}