This is a simple implementation of UTF-8 strings in C .

UTF8string is based on std::string provided by the standard C library but has been implemented to support UTF-8 encoded strings.

Some functions have been adapted for utf8 strings :

• utf8_length : get number of characters in a string (number of codepoints).
• utf8_size : get get the memory size of the string (in byte).
• utf8_find : find a utf8 substring in the current string.
• utf8_substr : get a utf8 substring of the current string.
• utf8_at : get the codepoint at a specified position.
• utf8_pop : remove the last codepoint of the string.

You just need to include all of the .hpp and .cpp files from src/ in your project. For each file that uses UTF8string, include this piece of code :

#include "utf8_string.hpp"

UTF8string u8("がんばつて Gumichan");
UTF8string sub = u8.utf8_substr(0,5);
size_t pos = u8.utf8_find(UTF8string("chan"));
size_t sz  = u8.utf8_size();
size_t l   = u8.utf8_length();

std::cout << "u8 string: " << u8 << "\n";
std::cout << "utf8 substring from 0 to 5: " << sub << "\n";
std::cout << "utf8 codepoint at 2: " << u8.utf8_at(2) << "\n";
std::cout << "utf8 string \"chan\" at " << pos << "\n";
std::cout << "u8 string - memory size: " << sz << "; length: " << l << "\n\n";

for (auto s: sub)    // or for (const std::string& s: u8)
{
    std::cout << "-> " << s << "\n";
}

Output :

utf8 string: がんばつて Gumichan
utf8 substring from 0 to 5: がんばつて
utf8 codepoint at 2: ば
utf8 string "chan" at 10
u8 string - memory size: 24; length: 14

-> が
-> ん
-> ば
-> つ
-> て

• LunatiX

This library is under the MIT License.