string_view and Encoding

std::string_view can handle different character encodings, but it doesn't process or interpret the encoding itself.

It provides a view over a sequence of characters, and the interpretation of those characters is up to you or the functions you pass the view to.

Handling Different Encodings

When working with different encodings, you need to ensure that the underlying data matches the expected encoding of the functions or libraries you are using.

For example, if you're dealing with UTF-8 encoded strings, you can use std::string_view to view those strings, but any encoding-specific operations (like converting to UTF-16) need to be handled explicitly.

Example with UTF-8

Here’s an example of using std::string_view with UTF-8 encoded strings:

1#include <iostream>
2#include <string_view>
3#include <string>
4
5void printStringView(std::string_view sv) {
6  std::cout << sv << '\n';
7}
8
9int main() {
10  auto utf8_str = reinterpret_cast<const char*>(
11    u8"Hello, 🌍"
12  );
13  std::string utf8_std_str = utf8_str;
14  std::string_view view{utf8_std_str};
15
16  printStringView(view);
17}

1Hello, 🌍

Converting Encodings

If you need to convert between encodings, you might use a library like ICU or codecvt. Here’s an example converting UTF-8 to UTF-16 using std::wstring and std::wstring_convert:

1#include <iostream>
2#include <string>
3#include <string_view>
4#include <codecvt>
5#include <locale>
6
7std::wstring utf8_to_utf16(std::string_view sv) {
8  std::wstring_convert<std::codecvt_utf8_utf16<
9    wchar_t>> converter;
10  return converter.from_bytes(
11    sv.data(), sv.data() + sv.size()
12  );
13}
14
15int main() {
16  const char8_t* utf8_char8_str = u8"Hello, 🌍";
17  std::string utf8_str(
18    reinterpret_cast<const char*>(utf8_char8_str)
19  );
20  std::string_view utf8_view(utf8_str);
21  std::wstring utf16_str =
22    utf8_to_utf16(utf8_view);
23
24  std::wcout << utf16_str;
25}

1Hello, 🌍

Summary

std::string_view itself is encoding-agnostic. It simply provides a view over a sequence of characters.

The responsibility of correctly interpreting and converting these characters according to their encoding falls to the programmer and any specialized libraries or functions used.

Always ensure the encoding of the underlying string is compatible with the operations being performed.