sm::crc32

A constexpr CRC-32 checksum

import sm.crc32;

Module file: sm/crc32.cppm

Table of Contents

• Summary

Summary

a constexpr-capable port of Ivor Wanders’ CRC-32 gist (MIT licensed), itself based on the ‘crc-32’ polynomial from Python’s crcmod module.

sm::crc32 is a single function computing the standard CRC-32 checksum of a string:

std::uint32_t crc = sm::crc32 (a_string); // a_string is a std::string, or anything that converts to std::string_view

Because it takes a std::string_view and is constexpr, it can be evaluated at compile time - most usefully, as a case label in a switch statement, letting you dispatch on string content without a chain of if/else string comparisons:

using std::literals::string_view_literals::operator""sv;

switch (sm::crc32 (some_runtime_string)) {
case sm::crc32 ("abc"sv):
    std::cout << "Matched abc" << std::endl;
    break;
default:
    std::cout << "No match" << std::endl;
}

This page was authored with AI, based on human written code in crc32.cppm. Reviewed by Seb James