Добавлена вторая задача пятой главы

Занимательное программирование/5/2_grey/main.cpp

@@ -0,0 +1,72 @@
+#include <cstring>
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include "grey.hpp"
+#include "huffman.hpp"
+
+std::vector<std::uint8_t> read_file(char *filename)
+{
+    std::ifstream input_file{ filename, std::ios::binary | std::ios::in };
+    input_file.exceptions(std::ios::badbit | std::ios::failbit);
+
+    return std::vector<std::uint8_t>{ std::istreambuf_iterator<char>(input_file), {} };
+}
+
+int show_usage()
+{
+    std::cerr << "Usage: grey (compress|decompress) input_file output_file." << std::endl;
+    return 1;
+}
+
+enum class direction {
+    compress,
+    decompress
+};
+
+int main(int argc, char **argv)
+{
+    direction operation;
+    if (argc != 4)
+    {
+        return show_usage();
+    }
+    if (std::strcmp(argv[1], "compress") == 0)
+    {
+        operation = direction::compress;
+    }
+    else if (std::strcmp(argv[1], "decompress") == 0)
+    {
+        operation = direction::decompress;
+    }
+    else
+    {
+        return show_usage();
+    }
+    switch (operation)
+    {
+    case direction::compress:
+        try {
+            std::ofstream output_file{ argv[3], std::ios::binary | std::ios::out | std::ios::trunc };
+            output_file.exceptions(std::ios::badbit | std::ios::failbit);
+
+            auto rle_stream = to_rle(argv[2]);
+            compress(rle_stream, output_file);
+            break;
+        }
+        catch (const std::runtime_error& e)
+        {
+            std::cerr << "Error decoding \"" << argv[2] << "\": " << e.what() << '.' << std::endl;
+            return 2;
+        }
+    case direction::decompress:
+        {
+            auto input = read_file(argv[2]);
+            std::stringstream rle_stream;
+            decompress(input, rle_stream);
+            from_rle(rle_stream.str(), argv[3]);
+        }
+        break;
+    }
+    return 0;
+}