Add strip_if functions

libmamba/include/mamba/core/util_string.hpp

@@ -10,11 +10,12 @@
 #include <algorithm>
 #include <cstring>
 #include <iomanip>
-#include <ostream>
+#include <iterator>
 #include <sstream>
 #include <string>
 #include <string_view>
 #include <type_traits>
+#include <utility>
 #include <vector>
 
 #include "mamba/core/util_compare.hpp"
@@ -26,8 +27,32 @@ namespace mamba
      */
     const char* raw_str_or_empty(const char* ptr);
 
+    /**
+     * Safe non utf-8 wrapping of <cctype> (see its doc).
+     */
+    bool is_control(char c);
+    bool is_control(wchar_t c);
+    bool is_print(char c);
+    bool is_print(wchar_t c);
+    bool is_space(char c);
+    bool is_space(wchar_t c);
+    bool is_blank(char c);
+    bool is_blank(wchar_t c);
+    bool is_graphic(char c);
+    bool is_graphic(wchar_t c);
+    bool is_digit(char c);
+    bool is_digit(wchar_t c);
+    bool is_alpha(char c);
+    bool is_alpha(wchar_t c);
+    bool is_alphanum(char c);
+    bool is_alphanum(wchar_t c);
+    bool is_lower(char c);
+    bool is_lower(wchar_t c);
+    bool is_upper(char c);
+    bool is_upper(wchar_t c);
     char to_lower(char c);
     wchar_t to_lower(wchar_t c);
+
     std::string to_lower(std::string_view str);
     std::wstring to_lower(std::wstring_view str);
     // The use of a template here serves to exclude the overload for const Char*
@@ -75,20 +100,35 @@ namespace mamba
     std::string_view lstrip(std::string_view input);
     std::wstring_view lstrip(std::wstring_view input);
 
+    template <typename UnaryFunc>
+    std::string_view lstrip_if(std::string_view input, UnaryFunc should_strip);
+    template <typename UnaryFunc>
+    std::wstring_view lstrip_if(std::wstring_view input, UnaryFunc should_strip);
+
     std::string_view rstrip(std::string_view input, char c);
     std::wstring_view rstrip(std::wstring_view input, wchar_t c);
     std::string_view rstrip(std::string_view input, std::string_view chars);
     std::wstring_view rstrip(std::wstring_view input, std::wstring_view chars);
     std::string_view rstrip(std::string_view input);
     std::wstring_view rstrip(std::wstring_view input);
 
+    template <typename UnaryFunc>
+    std::string_view rstrip_if(std::string_view input, UnaryFunc should_strip);
+    template <typename UnaryFunc>
+    std::wstring_view rstrip_if(std::wstring_view input, UnaryFunc should_strip);
+
     std::string_view strip(std::string_view input, char c);
     std::wstring_view strip(std::wstring_view input, wchar_t c);
     std::string_view strip(std::string_view input, std::string_view chars);
     std::wstring_view strip(std::wstring_view input, std::wstring_view chars);
     std::string_view strip(std::string_view input);
     std::wstring_view strip(std::wstring_view input);
 
+    template <typename UnaryFunc>
+    std::string_view strip_if(std::string_view input, UnaryFunc should_strip);
+    template <typename UnaryFunc>
+    std::wstring_view strip_if(std::wstring_view input, UnaryFunc should_strip);
+
     std::vector<std::string>
     split(std::string_view input, std::string_view sep, std::size_t max_split = SIZE_MAX);
     std::vector<std::wstring>
@@ -251,6 +291,78 @@ namespace mamba
     extern template bool starts_with_any(std::string_view, const std::vector<std::string>&);
     extern template bool starts_with_any(std::string_view, const std::vector<std::string_view>&);
 
+    /***************************************
+     *  Implementation of strip functions  *
+     ***************************************/
+
+    namespace detail
+    {
+        template <typename Char, typename UnaryFunc>
+        std::basic_string_view<Char>
+        lstrip_if_impl(std::basic_string_view<Char> input, UnaryFunc should_strip)
+        {
+            const auto start_iter = std::find_if(
+                input.cbegin(),
+                input.cend(),
+                [&should_strip](Char c) -> bool { return !should_strip(c); }
+            );
+            const auto start_idx = static_cast<std::size_t>(start_iter - input.cbegin());
+            return input.substr(start_idx);
+        }
+    }
+
+    template <typename UnaryFunc>
+    std::string_view lstrip_if(std::string_view input, UnaryFunc should_strip)
+    {
+        return detail::lstrip_if_impl(input, std::move(should_strip));
+    }
+
+    template <typename UnaryFunc>
+    std::wstring_view lstrip_if(std::wstring_view input, UnaryFunc should_strip)
+    {
+        return detail::lstrip_if_impl(input, std::move(should_strip));
+    }
+
+    namespace detail
+    {
+        template <typename Char, typename UnaryFunc>
+        std::basic_string_view<Char>
+        rstrip_if_impl(std::basic_string_view<Char> input, UnaryFunc should_strip)
+        {
+            const auto rstart_iter = std::find_if(
+                input.crbegin(),
+                input.crend(),
+                [&should_strip](Char c) -> bool { return !should_strip(c); }
+            );
+            const auto past_end_idx = static_cast<std::size_t>(input.crend() - rstart_iter);
+            return input.substr(0, past_end_idx);
+        }
+    }
+
+    template <typename UnaryFunc>
+    std::string_view rstrip_if(std::string_view input, UnaryFunc should_strip)
+    {
+        return detail::rstrip_if_impl(input, std::move(should_strip));
+    }
+
+    template <typename UnaryFunc>
+    std::wstring_view rstrip_if(std::wstring_view input, UnaryFunc should_strip)
+    {
+        return detail::rstrip_if_impl(input, std::move(should_strip));
+    }
+
+    template <typename UnaryFunc>
+    std::string_view strip_if(std::string_view input, UnaryFunc should_strip)
+    {
+        return rstrip_if(lstrip_if(input, should_strip), should_strip);
+    }
+
+    template <typename UnaryFunc>
+    std::wstring_view strip_if(std::wstring_view input, UnaryFunc should_strip)
+    {
+        return rstrip_if(lstrip_if(input, should_strip), should_strip);
+    }
+
     /**************************************
      *  Implementation of join functions  *
      **************************************/
@@ -286,7 +398,7 @@ namespace mamba
         }
     }
 
-    // TODO(C++20) Take an input range and return a range
+    // TODO(C++20) Use ``std::ranges::join_view`` (or ``std::ranges::join``)
     template <typename InputIt, typename UnaryFunction, typename Value>
     UnaryFunction join_for_each(InputIt first, InputIt last, UnaryFunction func, const Value& sep)
     {