Download Better: Runtime C++

DownloadManager::~DownloadManager() cancel(); if (m_downloadThread.joinable()) m_downloadThread.join(); if (m_curl) curl_easy_cleanup(m_curl); curl_global_cleanup();

int main() DownloadManager dm; DownloadManager::DownloadOptions options; options.url = "https://example.com/file.zip"; options.output_path = "downloaded_file.zip"; options.max_retries = 2; options.resume_on_failure = true; std::cout << "Starting download..." << std::endl; auto start_time = std::chrono::steady_clock::now(); // Async download with callbacks dm.downloadAsync(options, // Progress callback [](float progress, size_t downloaded, size_t total) std::cout << "\rProgress: " << (progress * 100) << "% (" << downloaded << "/" << total << " bytes)" << std::flush; , // Complete callback [&start_time](bool success, const std::string& error) auto end_time = std::chrono::steady_clock::now(); auto duration = std::chrono::duration_cast<std::chrono::seconds>(end_time - start_time); if (success) std::cout << "\nDownload completed in " << duration.count() << " seconds!" << std::endl; else std::cout << "\nDownload failed: " << error << std::endl; ); // Wait for completion while (dm.isActive()) std::this_thread::sleep_for(std::chrono::milliseconds(100)); return 0; runtime c++ download

find_package(CURL REQUIRED)

private: static size_t writeCallback(void* contents, size_t size, size_t nmemb, void* userp); static int progressCallback(void* userp, curl_off_t dltotal, curl_off_t dlnow, curl_off_t ultotal, curl_off_t ulnow); struct DownloadContext std::ofstream file; size_t downloaded_bytes = 0; size_t total_bytes = 0; ProgressCallback progress_cb; std::string output_path; bool resume_mode = false; ; std::unique_ptr<DownloadContext> m_context; std::thread m_downloadThread; std::atomic<bool> m_activefalse; std::atomic<bool> m_cancelfalse; std::string m_lastError; CURL* m_curl; ; if (m_downloadThread.joinable()) m_downloadThread.join()

// download_manager.h #pragma once #include <string> #include <functional> #include <thread> #include <atomic> #include <fstream> #include <memory> #include <curl/curl.h> if (m_curl) curl_easy_cleanup(m_curl)

// Helper: Get file size size_t getFileSize(const std::string& path) struct stat stat_buf; if (stat(path.c_str(), &stat_buf) == 0) return stat_buf.st_size; return 0;

size_t DownloadManager::writeCallback(void* contents, size_t size, size_t nmemb, void* userp) size_t real_size = size * nmemb; auto* ctx = static_cast<DownloadContext*>(userp); if (ctx->file.is_open()) ctx->file.write(static_cast<char*>(contents), real_size); ctx->downloaded_bytes += real_size; // Trigger progress callback if (ctx->progress_cb && ctx->total_bytes > 0) float progress = (float)ctx->downloaded_bytes / ctx->total_bytes; ctx->progress_cb(progress, ctx->downloaded_bytes, ctx->total_bytes); return real_size; return 0;