Add neopg compress.

Author: lambdafu

include/neopg/cli/compress_command.h

@@ -0,0 +1,47 @@
+/* Command line parsing
+   Copyright 2017 The NeoPG developers
+
+   NeoPG is released under the Simplified BSD License (see license.txt)
+*/
+
+#pragma once
+
+#include <neopg/cli/command.h>
+
+namespace NeoPG {
+namespace CLI {
+
+class ListCompressCommand : public Command {
+ public:
+  ListCompressCommand(CLI::App& app, const std::string& flag,
+                      const std::string& description,
+                      const std::string& group_name = "")
+      : Command(app, flag, description, group_name) {}
+  void run();
+};
+
+class CompressCommand : public Command {
+ public:
+  std::vector<std::string> m_files;
+  std::string m_algo{"gz"};
+  int m_level = 0;
+  bool m_decode = false;
+  const std::string group = "Commands";
+  ListCompressCommand cmd_list;
+
+  void run() override;
+  CompressCommand(CLI::App& app, const std::string& flag,
+                  const std::string& description,
+                  const std::string& group_name = "")
+      : Command(app, flag, description, group_name),
+        cmd_list(m_cmd, "list", "list supported compression functions", group) {
+    m_cmd.add_flag("-d,--decompress", m_decode,
+                   "decompress already compressed data");
+    m_cmd.add_option("file", m_files, "file to hash");
+    m_cmd.add_option("--algo", m_algo, "compression function", true);
+    m_cmd.add_option("--level", m_level, "compression level (0 default, 1-9)");
+  }
+};
+
+}  // Namespace CLI
+}  // Namespace NeoPG

src/CMakeLists.txt

@@ -205,13 +205,15 @@ add_executable(neopg
   ../include/neopg/cli/hash_command.h
   ../include/neopg/cli/armor_command.h
   ../include/neopg/cli/cat_command.h
+  ../include/neopg/cli/compress_command.h
   cli/command.cpp
   cli/version_command.cpp
   cli/packet_command.cpp
   cli/random_command.cpp
   cli/hash_command.cpp
   cli/armor_command.cpp
   cli/cat_command.cpp
+  cli/compress_command.cpp
   neopg.cpp
 )
 target_include_directories(neopg PRIVATE

src/cli/compress_command.cpp

@@ -0,0 +1,72 @@
+/* NeoPG
+   Copyright 2017 The NeoPG developers
+
+   NeoPG is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <iostream>
+#include <map>
+
+#include <botan/comp_filter.h>
+#include <botan/compression.h>
+#include <botan/filters.h>
+
+#include <neopg/cli/compress_command.h>
+
+namespace NeoPG {
+namespace CLI {
+
+void ListCompressCommand::run() {
+  std::cout << "Any Botan-compatible algorithm specifier can be used:\n\n";
+#if defined(BOTAN_HAS_ZLIB)
+  std::cout << "Zlib, zlib\n";
+  std::cout << "Gzip, gzip, gz\n";
+  std::cout << "Deflate, deflate\n";
+#endif
+
+#if defined(BOTAN_HAS_BZIP2)
+  std::cout << "bzip2, bz2, Bzip2\n";
+#endif
+
+#if defined(BOTAN_HAS_LZMA)
+  std::cout << "lzma, xz, LZMA";
+#endif
+}
+
+const std::map<std::string, std::string> algo_to_suffix = {
+    {"Deflate_Compression", ".zip"},
+    {"Zlib_Compression", ".zlib"},
+    {"Gzip_Compression", ".gz"},
+    {"Bzip2_Compression", ".bz2"},
+    {"Lzma_Compression", ".xz"}};
+
+void CompressCommand::run() {
+  bool multi_files = false;
+
+  if (!m_cmd.get_subcommands().empty()) return;
+
+  if (m_files.empty()) m_files.emplace_back("-");
+
+  std::unique_ptr<Botan::Compression_Algorithm> compressor{
+      Botan::make_compressor(m_algo)};
+  if (!compressor) throw Botan::Lookup_Error("Compression", m_algo, "");
+  const std::string suffix(algo_to_suffix.at(compressor->name()));
+
+  for (auto& file : m_files) {
+    std::unique_ptr<Botan::DataSource_Stream> source{
+        (file == "-") ? new Botan::DataSource_Stream{std::cin}
+                      : new Botan::DataSource_Stream{file}};
+    Botan::Filter* compress =
+        m_decode
+            ? (Botan::Filter*)new Botan::Decompression_Filter(m_algo)
+            : (Botan::Filter*)new Botan::Compression_Filter(m_algo, m_level);
+    Botan::Filter* sink = (file == "-")
+                              ? new Botan::DataSink_Stream(std::cout)
+                              : new Botan::DataSink_Stream(file + suffix, true);
+    Botan::Pipe pipe{compress, sink};
+    pipe.process_msg(*source);
+  }
+}
+
+}  // Namespace CLI
+}  // Namespace NeoPG

src/neopg.cpp

@@ -11,6 +11,7 @@
 #include <neopg/cli/armor_command.h>
 #include <neopg/cli/cat_command.h>
 #include <neopg/cli/command.h>
+#include <neopg/cli/compress_command.h>
 #include <neopg/cli/hash_command.h>
 #include <neopg/cli/packet_command.h>
 #include <neopg/cli/random_command.h>
@@ -115,6 +116,8 @@ int main(int argc, char* argv[]) {
                            tools_group);
   RandomCommand cmd_random(app, "random", "output random bytes", tools_group);
   HashCommand cmd_hash(app, "hash", "calculate hash function", tools_group);
+  CompressCommand cmd_compress(app, "compress", "compress and decompress data",
+                               tools_group);
   ArmorCommand cmd_armor(app, "armor", "ASCII-encode and decode binary data",
                          tools_group);
   CatCommand cmd_cat(app, "cat", "the beginning of a new Unix system",