picomap/firmware/include/usb_cdc.h

#pragma once
#include <cstdint>
#include <span>
#include <vector>
#include "tusb.h"
#include "ring_buffer.h"

struct usb_cdc {
    ring_buffer<uint8_t, 8192> tx;

    bool send(std::span<const uint8_t> data) {
        if (!tx.push(data)) return false;
        drain();
        return true;
    }

    void send(const std::vector<uint8_t>& data) {
        send(std::span<const uint8_t>{data});
    }

    void drain() {
        while (!tx.empty()) {
            uint32_t avail = tud_cdc_write_available();
            if (avail == 0) break;
            auto chunk = tx.read_contiguous();
            if (chunk.size() > avail) chunk = chunk.first(avail);
            tud_cdc_write(chunk.data(), chunk.size());
            tx.consume(chunk.size());
        }
        tud_cdc_write_flush();
    }
};