interleave-deinterleave.cpp

#include <fmt/core.h>
#include <vector>

using stream_t = std::vector<double>;
using split_t = std::vector<stream_t>;

auto deinterleave(stream_t framesstream, int nchannel){
    auto nframe = framesstream.size();

    split_t res(nchannel);

    for(auto& c : res){
        c.reserve(nframe/nchannel);
    }

    for(size_t i = 0; i < nframe; i++){
        res[i%nchannel].push_back(framesstream[i]);
    }

    return res;
}

auto interleave(split_t splitstream, int nchannel){
    size_t nframe = 0;

    for(const auto& c : splitstream){
        for(const auto& s: c){
            nframe++;
        }
    }

    stream_t res(nframe);

    for(size_t i = 0, j = 0; i < nframe; j++){
        for(size_t k = 0; k < nchannel && i < nframe; k++, i++){
            res[i] = splitstream[k][j];
        }
    }

    return res;
}

int main(){

    stream_t m(64);
    double i = 0.0;

    for(auto& s : m){
        s = (i += 1.0);
    }

    int cn = 4;

    auto x = deinterleave(m, cn);

    for(const auto& c : x){
        fmt::print("[{} in {}] ", c.size(), c.capacity());
        for(const auto& s : c){
            fmt::print("{} ", s);
        }
        fmt::print("\n");
    }

    stream_t n = interleave(x, cn);

    fmt::print("[{} in {}] ", n.size(), n.capacity());

    for(const auto& s : n){
        fmt::print("{} ", s);
    }
}