diff options
Diffstat (limited to '3rdparty/asio/src/examples/cpp03/spawn/parallel_grep.cpp')
-rw-r--r-- | 3rdparty/asio/src/examples/cpp03/spawn/parallel_grep.cpp | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/3rdparty/asio/src/examples/cpp03/spawn/parallel_grep.cpp b/3rdparty/asio/src/examples/cpp03/spawn/parallel_grep.cpp new file mode 100644 index 00000000000..d742f196d78 --- /dev/null +++ b/3rdparty/asio/src/examples/cpp03/spawn/parallel_grep.cpp @@ -0,0 +1,89 @@ +// +// parallel_grep.cpp +// ~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com) +// +// Distributed under the Boost Software License, Version 1.0. (See accompanying +// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// + +#include <asio/dispatch.hpp> +#include <asio/post.hpp> +#include <asio/spawn.hpp> +#include <asio/strand.hpp> +#include <asio/thread_pool.hpp> +#include <boost/bind.hpp> +#include <fstream> +#include <iostream> +#include <string> + +using asio::dispatch; +using asio::spawn; +using asio::strand; +using asio::thread_pool; +using asio::yield_context; + +void print_match(std::string input_file, std::string line) +{ + std::cout << input_file << ':' << line << std::endl; +} + +void search_file(std::string search_string, std::string input_file, + strand<thread_pool::executor_type> output_strand, yield_context yield) +{ + std::ifstream is(input_file.c_str()); + std::string line; + std::size_t line_num = 0; + while (std::getline(is, line)) + { + // If we find a match, send a message to the output. + if (line.find(search_string) != std::string::npos) + { + dispatch(output_strand, boost::bind(&print_match, input_file, line)); + } + + // Every so often we yield control to another coroutine. + if (++line_num % 10 == 0) + post(yield); + } +} + +int main(int argc, char* argv[]) +{ + try + { + if (argc < 2) + { + std::cerr << "Usage: parallel_grep <string> <files...>\n"; + return 1; + } + + // We use a fixed size pool of threads for reading the input files. The + // number of threads is automatically determined based on the number of + // CPUs available in the system. + thread_pool pool; + + // To prevent the output from being garbled, we use a strand to synchronise + // printing. + strand<thread_pool::executor_type> output_strand(pool.get_executor()); + + // Spawn a new coroutine for each file specified on the command line. + std::string search_string = argv[1]; + for (int argn = 2; argn < argc; ++argn) + { + std::string input_file = argv[argn]; + spawn(pool, boost::bind(&search_file, + search_string, input_file, output_strand, _1)); + } + + // Join the thread pool to wait for all the spawned tasks to complete. + pool.join(); + } + catch (std::exception& e) + { + std::cerr << "Exception: " << e.what() << "\n"; + } + + return 0; +} |