Add ex_netcompat.cc example.

example/CMakeLists.txt

@@ -2,10 +2,11 @@ cmake_minimum_required(VERSION 3.12)
 project(libswoc_examples CXX)
 set(CMAKE_CXX_STANDARD 17)
 
-add_executable(ex_netdb
-    ex_netdb.cc
-    )
-
-target_link_libraries(ex_netdb PUBLIC swoc++)
+add_executable(ex_netdb ex_netdb.cc)
+target_link_libraries(ex_netdb PUBLIC libswoc)
 set_target_properties(ex_netdb PROPERTIES CLANG_FORMAT_DIRS ${CMAKE_CURRENT_SOURCE_DIR})
-target_compile_options(ex_netdb PRIVATE -Wall -Wextra -Werror -Wno-unused-parameter -Wno-format-truncation -Wno-stringop-overflow -Wno-invalid-offsetof)
+target_compile_options(ex_netdb PRIVATE -Wall -Wextra -Werror)
+
+add_executable(ex_netcompact ex_netcompact.cc)
+target_link_libraries(ex_netcompact PUBLIC libswoc)
+target_compile_options(ex_netcompact PRIVATE -Wall -Wextra -Werror)

example/ex_netcompact.cc

@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright 2014 Network Geographics
+
+/** @file
+
+    Example tool to compact networks.
+
+    Input is a file with addresses. Each line should be an address, an address range,
+    or a network in CIDR format.
+
+    4441:34F8:1E40:1EF:0:0:A0:0/108
+    192.168.12.1
+    10.0.23.0/23
+
+    The output is the same set of addresses in as few networks as possible.
+*/
+
+#include <unordered_set>
+#include <fstream>
+
+#include "swoc/TextView.h"
+#include "swoc/swoc_ip.h"
+#include "swoc/bwf_ip.h"
+#include "swoc/bwf_std.h"
+#include "swoc/bwf_std.h"
+#include "swoc/swoc_file.h"
+
+using namespace std::literals;
+using namespace swoc::literals;
+
+using swoc::TextView;
+
+using swoc::IPAddr;
+using swoc::IPRange;
+
+/// Type for temporary buffer writer output.
+using W = swoc::LocalBufferWriter<512>;
+
+/// IPSpace for mapping address to @c Payload
+using Space = swoc::IPSpace<std::monostate>;
+
+/// Process the @a content of a file in to @a space.
+unsigned process(Space& space, TextView content) {
+  int line_no = 0; /// Track for error reporting.
+  unsigned n_ranges = 0;
+
+  // For each line in @a content
+  for  (TextView line ; ! (line = content.take_prefix_at('\n')).empty() ; ) {
+    ++line_no;
+    line.trim_if(&isspace);
+    // Allow empty lines and '#' comments without error.
+    if (line.empty() || '#' == *line) {
+      continue;
+    }
+
+    // Get the range, make sure it's a valid range.
+    IPRange range{line};
+    if (range.empty()) {
+      std::cerr << W().print("Invalid range '{}' on line {}\n", line, line_no);
+      continue;
+    }
+    ++n_ranges;
+    space.mark(range, std::monostate{});
+  }
+  return n_ranges;
+}
+
+int main(int argc, char *argv[]) {
+  Space space;
+
+  if (argc < 2) {
+    std::cerr << W().print("Input file name required.");
+    exit(1);
+  }
+
+  auto t0 = std::chrono::system_clock::now();
+  swoc::file::path path{argv[1]};
+  std::error_code ec;
+  std::string content = swoc::file::load(path, ec);
+  if (ec) {
+    std::cerr << W().print(R"(Failed to open file "{}" - {}\n)", path, ec);
+    exit(1);
+  }
+  auto n_ranges = process(space, content);
+
+  // Dump the resulting space.
+  unsigned n_nets = 0;
+  for ( auto && [ r, p] : space) {
+    for ( auto && net : r.networks()) {
+      ++n_nets;
+      std::cout << W().print("{}\n", net);
+    }
+  }
+
+  auto delta = std::chrono::system_clock::now() - t0;
+
+  std::cout << W().print("{} ranges in, {} ranges condensed, {} networks out in {} ms\n"
+    , n_ranges, space.count(), n_nets
+    , std::chrono::duration_cast<std::chrono::milliseconds>(delta).count());
+
+  return 0;
+}