utfz - a tiny C++ library for parsing and encoding utf-8

The goal of this library is to provide a tiny set of utilities that make it easy to iterate over the code points of a UTF8 string, as well as build up a UTF8 string from 32-bit integer code points.

• Header-only (utfz.hpp), or two source files (utfz.cpp and utfz.h)
• Does not throw exceptions
• 100% line coverage in tests
• All iteration methods support both null terminated strings, and explicit length strings
• Checks for all invalid code points (overlong sequences, UTF-16 surrogate pairs, 0xFFFE, 0xFFFF)
• Returns the replacement character U+FFFD for any invalid sequences, and continues parsing on the next plausible code point

Example of printing code points to the console:

const char* a_utf8_string;
for (int cp : utfz::cp(a_utf8_string))
    printf("%d ", cp);

Example of tolower using std::string:

std::string input;
std::string low;
for (int cp : utfz::cp(input))
    utfz::encode(low, ::tolower(cp));
// 'low' now contains the lower-case representation of 'input'

Iterating manually, over a null terminated string:

const char* pos = input; // input is const char*
int cp;
while (utfz::next(pos, cp))
	printf("%d ", cp);

Iterating manually, over a string with known length:

const char* pos = input;       // input is const char*
const char* end = input + len;
int cp;
while (utfz::next(pos, end, cp))
	printf("%d ", cp);