Support for stdstring view

CMakeLists.txt

@@ -34,6 +34,9 @@ option(HIGHFIVE_VERBOSE "Set logging level to verbose." OFF)
 option(HIGHFIVE_HAS_FRIEND_DECLARATIONS "Enable additional friend declarations. Certain compiler require this On, others Off." OFF)
 mark_as_advanced(HIGHFIVE_HAS_FRIEND_DECLARATIONS)
 
+option(HIGHFIVE_USE_STRING_VIEW "Use std::string_view instead of std::string has H5 objects keys." OFF)
+mark_as_advanced(HIGHFIVE_HAS_STRING_VIEW_NAMES)
+
 option(HIGHFIVE_FIND_HDF5 "Find and link with HDF5." On)
 
 set(HIGHFIVE_CMAKE_INSTALL_DIR "lib/cmake/HighFive" CACHE STRING
@@ -100,6 +103,12 @@ if(CMAKE_CXX_STANDARD EQUAL 98 OR CMAKE_CXX_STANDARD LESS ${HIGHFIVE_CXX_STANDAR
   message(FATAL_ERROR "HighFive needs to be compiled with at least C++${HIGHFIVE_CXX_STANDARD_DEFAULT}")
 endif()
 
+if(HIGHFIVE_USE_STRING_VIEW)
+  if(CMAKE_CXX_STANDARD LESS 17)
+    message(FATAL_ERROR "HighFive needs to be compiled with at least C++17 to use std::string_view as keys")
+  endif()
+endif()
+
 if(HIGHFIVE_TEST_MDSPAN AND CMAKE_CXX_STANDARD LESS 23)
   message(FATAL_ERROR "HIGHFIVE_TEST_MDSPAN requires C++23 or newer, but CMAKE_CXX_STANDARD is ${CMAKE_CXX_STANDARD}")
 endif()

cmake/HighFiveFlags.cmake

@@ -24,6 +24,10 @@ if(HIGHFIVE_HAS_FRIEND_DECLARATIONS)
     target_compile_definitions(HighFiveFlags INTERFACE -DHIGHFIVE_HAS_FRIEND_DECLARATIONS=1)
 endif()
 
+if(HIGHFIVE_USE_STRING_VIEW)
+    target_compile_definitions(HighFiveFlags INTERFACE -DHIGHFIVE_USE_STRING_VIEW=1)
+endif()
+
 if(HIGHFIVE_SANITIZER)
     target_compile_options(HighFiveFlags INTERFACE -fsanitize=${HIGHFIVE_SANITIZER})
     target_link_options(HighFiveFlags INTERFACE -fsanitize=${HIGHFIVE_SANITIZER})

include/highfive/H5File.hpp

@@ -13,12 +13,12 @@
 
 #include "H5Object.hpp"
 #include "H5PropertyList.hpp"
+#include "H5Label.hpp"
 #include "bits/H5Annotate_traits.hpp"
 #include "bits/H5Node_traits.hpp"
 
 namespace HighFive {
 
-
 ///
 /// \brief File class
 ///
@@ -68,7 +68,7 @@ class File: public Object, public NodeTraits<File>, public AnnotateTraits<File>
     /// \param fileAccessProps: the file access properties
     ///
     /// Open or create a new HDF5 file
-    explicit File(const std::string& filename,
+    explicit File(const H5Label& filename,
                   AccessMode openFlags = ReadOnly,
                   const FileAccessProps& fileAccessProps = FileAccessProps::Default());
 
@@ -80,7 +80,7 @@ class File: public Object, public NodeTraits<File>, public AnnotateTraits<File>
     /// \param fileAccessProps: the file access properties
     ///
     /// Open or create a new HDF5 file
-    File(const std::string& filename,
+    File(const H5Label& filename,
          AccessMode access_mode,
          const FileCreateProps& fileCreateProps,
          const FileAccessProps& fileAccessProps = FileAccessProps::Default());

include/highfive/H5Label.hpp

@@ -0,0 +1,66 @@
+/*
+ *  Copyright (c), 2026, Alain Miniussi <alain.miniussi@oca.eu>
+ *
+ *  Distributed under the Boost Software License, Version 1.0.
+ *    (See accompanying file LICENSE_1_0.txt or copy at
+ *          http://www.boost.org/LICENSE_1_0.txt)
+ *
+ */
+#pragma once
+
+#include <string>
+
+#if HIGHFIVE_USE_STRING_VIEW
+#  ifndef __cpp_lib_string_view
+#  error "std::string_view not available in this standard librarie
+#  include <string_view>
+#  endif
+#endif
+
+namespace HighFive {
+/// \brief Build a path composed of all parameter separated with a "/".
+/// \param s can be a std::string, a std::string_view (if supposrted) or a const char*.
+/// \return The build path
+inline std::string path(std::string s) { return s; }
+/// \overload
+template<typename... S> inline std::string path(std::string first, S... s);
+
+#if HIGHFIVE_USE_STRING_VIEW
+using H5Label = std::string_view;
+
+/// \overload
+inline std::string path(std::string_view s) { return std::string{s}; }
+/// \overload
+inline std::string path(char const* s) { return std::string{s}; }
+/// \overload
+template<typename... S> std::string path(std::string_view first, S... s);
+template<typename... S> std::string path(char const* first, S... s);
+
+#else // !HIGHFIVE_USE_STRING_VIEW
+
+using H5Label = std::string;
+
+#endif // HIGHFIVE_USE_STRING_VIEW
+
+template<typename... S>
+inline
+std::string path(std::string first, S... s) {
+    return first + "/" + path(s...);
+}
+
+#if HIGHFIVE_USE_STRING_VIEW
+
+template<typename... S>
+inline
+std::string path(std::string_view first, S... s) {
+    return std::string{first} + "/" + path(s...);
+}
+
+template<typename... S>
+inline
+std::string path(char const* first, S... s) {
+    return std::string{first} + "/" + path(s...);
+}
+
+#endif
+}

include/highfive/bits/H5Annotate_traits.hpp

@@ -10,6 +10,7 @@
 
 #include <string>
 
+#include "../H5Label.hpp"
 #include "../H5Attribute.hpp"
 
 namespace HighFive {
@@ -24,7 +25,7 @@ class AnnotateTraits {
     /// \param type
     /// \return the attribute object
     ///
-    Attribute createAttribute(const std::string& attribute_name,
+    Attribute createAttribute(const H5Label& attribute_name,
                               const DataSpace& space,
                               const DataType& type);
 
@@ -36,7 +37,7 @@ class AnnotateTraits {
     /// informations
     /// \return Attribute Object
     template <typename Type>
-    Attribute createAttribute(const std::string& attribute_name, const DataSpace& space);
+    Attribute createAttribute(const H5Label& attribute_name, const DataSpace& space);
 
     ///
     /// \brief createAttribute create a new attribute on the current dataset and
@@ -47,18 +48,18 @@ class AnnotateTraits {
     /// \return Attribute Object
     ///
     template <typename T>
-    Attribute createAttribute(const std::string& attribute_name, const T& data);
+    Attribute createAttribute(const H5Label& attribute_name, const T& data);
 
     ///
     /// \brief deleteAttribute let you delete an attribute by its name.
     /// \param attribute_name identifier of the attribute
-    void deleteAttribute(const std::string& attribute_name);
+    void deleteAttribute(const H5Label& attribute_name);
 
     ///
     /// \brief open an existing attribute with the name attribute_name
     /// \param attribute_name identifier of the attribute
     /// \return the attribute object
-    Attribute getAttribute(const std::string& attribute_name) const;
+    Attribute getAttribute(const H5Label& attribute_name) const;
 
     ///
     /// \brief return the number of attributes of the node / group
@@ -73,7 +74,7 @@ class AnnotateTraits {
     ///
     /// \brief checks an attribute exists
     /// \return number of attributes
-    bool hasAttribute(const std::string& attr_name) const;
+    bool hasAttribute(const H5Label& attr_name) const;
 
   private:
     using derivate_type = Derivate;

include/highfive/bits/H5Annotate_traits_misc.hpp

@@ -21,11 +21,11 @@
 namespace HighFive {
 
 template <typename Derivate>
-inline Attribute AnnotateTraits<Derivate>::createAttribute(const std::string& attribute_name,
+inline Attribute AnnotateTraits<Derivate>::createAttribute(const H5Label& attribute_name,
                                                            const DataSpace& space,
                                                            const DataType& dtype) {
     auto attr_id = detail::h5a_create2(static_cast<Derivate*>(this)->getId(),
-                                       attribute_name.c_str(),
+                                       std::string{attribute_name}.c_str(),
                                        dtype.getId(),
                                        space.getId(),
                                        H5P_DEFAULT,
@@ -35,14 +35,14 @@ inline Attribute AnnotateTraits<Derivate>::createAttribute(const std::string& at
 
 template <typename Derivate>
 template <typename Type>
-inline Attribute AnnotateTraits<Derivate>::createAttribute(const std::string& attribute_name,
+inline Attribute AnnotateTraits<Derivate>::createAttribute(const H5Label& attribute_name,
                                                            const DataSpace& space) {
     return createAttribute(attribute_name, space, create_and_check_datatype<Type>());
 }
 
 template <typename Derivate>
 template <typename T>
-inline Attribute AnnotateTraits<Derivate>::createAttribute(const std::string& attribute_name,
+inline Attribute AnnotateTraits<Derivate>::createAttribute(const H5Label& attribute_name,
                                                            const T& data) {
     Attribute att =
         createAttribute(attribute_name,
@@ -53,14 +53,14 @@ inline Attribute AnnotateTraits<Derivate>::createAttribute(const std::string& at
 }
 
 template <typename Derivate>
-inline void AnnotateTraits<Derivate>::deleteAttribute(const std::string& attribute_name) {
-    detail::h5a_delete(static_cast<const Derivate*>(this)->getId(), attribute_name.c_str());
+inline void AnnotateTraits<Derivate>::deleteAttribute(const H5Label& attribute_name) {
+    detail::h5a_delete(static_cast<const Derivate*>(this)->getId(), std::string{attribute_name}.c_str());
 }
 
 template <typename Derivate>
-inline Attribute AnnotateTraits<Derivate>::getAttribute(const std::string& attribute_name) const {
+inline Attribute AnnotateTraits<Derivate>::getAttribute(const H5Label& attribute_name) const {
     const auto attr_id = detail::h5a_open(static_cast<const Derivate*>(this)->getId(),
-                                          attribute_name.c_str(),
+                                          std::string{attribute_name}.c_str(),
                                           H5P_DEFAULT);
     return detail::make_attribute(attr_id);
 }
@@ -90,8 +90,8 @@ inline std::vector<std::string> AnnotateTraits<Derivate>::listAttributeNames() c
 }
 
 template <typename Derivate>
-inline bool AnnotateTraits<Derivate>::hasAttribute(const std::string& attr_name) const {
-    return detail::h5a_exists(static_cast<const Derivate*>(this)->getId(), attr_name.c_str()) > 0;
+inline bool AnnotateTraits<Derivate>::hasAttribute(const H5Label& attr_name) const {
+    return detail::h5a_exists(static_cast<const Derivate*>(this)->getId(), std::string{attr_name}.c_str()) > 0;
 }
 
 }  // namespace HighFive

include/highfive/bits/H5File_misc.hpp

@@ -47,13 +47,13 @@ inline unsigned convert_open_flag(File::AccessMode openFlags) {
 }
 }  // namespace
 
-inline File::File(const std::string& filename,
+inline File::File(const H5Label& filename,
                   AccessMode openFlags,
                   const FileAccessProps& fileAccessProps)
     : File(filename, openFlags, FileCreateProps::Default(), fileAccessProps) {}
 
 
-inline File::File(const std::string& filename,
+inline File::File(const H5Label& filename,
                   AccessMode access_mode,
                   const FileCreateProps& fileCreateProps,
                   const FileAccessProps& fileAccessProps) {
@@ -76,7 +76,7 @@ inline File::File(const std::string& filename,
             silencer = std::make_unique<SilenceHDF5>();
         }
 
-        _hid = detail::nothrow::h5f_open(filename.c_str(), openMode, fileAccessProps.getId());
+        _hid = detail::nothrow::h5f_open(std::string{filename}.c_str(), openMode, fileAccessProps.getId());
 
         if (isValid()) {
             return;  // Done
@@ -87,13 +87,13 @@ inline File::File(const std::string& filename,
             createMode = H5F_ACC_EXCL;
         } else {
             HDF5ErrMapper::ToException<FileException>(
-                std::string("Unable to open file " + filename));
+                std::string("Unable to open file " + std::string{filename}));
         }
     }
 
     auto fcpl = fileCreateProps.getId();
     auto fapl = fileAccessProps.getId();
-    _hid = detail::h5f_create(filename.c_str(), createMode, fcpl, fapl);
+    _hid = detail::h5f_create(std::string{filename}.c_str(), createMode, fcpl, fapl);
 }
 
 inline const std::string& File::getName() const {