consteval-huffman

Allows for long strings of text or data to be compressed at compile-time, with an efficient decoder routine for decompression at run-time. The decoder conforms to std::forward_iterator, allowing for use in ranged-for or standard algorithms.

Compression is achieved using Huffman coding, which works by creating short codes (measured in bits) for frequently-occuring characters. This works best on larger pieces of data, or more so data that is limited in its range of values (e.g. written text).

Use cases

1. Text configurations (e.g. JSON)

A ~3.5kB string of JSON can be compressed down ~2.5kB (see it on Godbolt).

2. Scripts (e.g. Lisp)

A ~40 line comment-including sample of Lisp can be reduced from 1,662 bytes to 1,244 (418 bytes saved) (Godbolt).

How to Use

#include "consteval_huffman.hpp"

constexpr static const char some_data_raw[] = /* insert text here */;

// Creates an object with the compressed data
// If data is not smaller after compression, huffman_compress will keep the data uncompressed
constinit static const auto some_data = huffman_compress<some_data_raw>();

// Or, with a set data length:
// ... some_data = huffman_compress<some_data_raw, 1500>();

int main()
{
    // Decompress and print out the data
    for (auto c : some_data)
        putchar(c);
}