First compression implementation, but file output is wrong

src/main.cc

@@ -1,6 +1,103 @@
+#include <cstdio>
+#include <fstream>
 #include <iostream>
+#include <map>
+#include <streambuf>
+#include <string>
+
+#ifdef Debug
+#define pdeb printf
+#else
+#define pdeb                                                                   \
+  if (0)                                                                       \
+  printf
+#endif
+
+using dic_t = std::map<std::pair<int, uint8_t>, int>;
+using std::printf;
+using std::puts;
+using ustring = std::basic_string<unsigned char>;
+using c32string = std::basic_string<uint32_t>;
+
+std::pair<bool, int> dico(dic_t &dictionary, int nr_chaine, uint8_t c) {
+  if(nr_chaine == -1)
+    return std::make_pair(true, c);
+  auto &e = dictionary[std::make_pair(nr_chaine, c)];
+  return (e) ? std::make_pair(true, e)
+             : std::make_pair(
+                   false,
+                   (e = static_cast<
+                            typename std::remove_reference<decltype(e)>::type>(
+                            dictionary.size()) +
+                        255));
+}
+
+const c32string compress(const ustring &text, dic_t &dictionary) {
+  c32string res{};
+  int w = -1;
+  for(const auto &c : text) {
+    if (const auto & [ exists, pos ] = dico(dictionary, w, c);
+        exists) {
+      w = pos;
+    } else {
+      res.push_back(static_cast<unsigned int>(w));
+      w = c;
+    }
+  }
+  return res;
+}
 
 int main(int argc, char *argv[]) {
-	std::cout << "Hello World!" << std::endl;
+  if (argc < 2) {
+    puts("Usage: lzw <filename>");
+    return 1;
+  } else {
+    for (int i = 0; i < argc; ++i)
+      printf("argv[%d] = %s\n", i, argv[i]);
+  }
+
+  // fichier d'entrée
+  std::ifstream t{argv[1]};
+
+  std::ofstream out{"outfile.lzw"};
+
+  // string contenant le fichier d'entrée
+  ustring str{};
+
+  // réserver la mémoire dans le string pour le fichier à compresser
+  t.seekg(0, std::ios::end);
+  str.reserve(static_cast<unsigned long>(t.tellg()));
+  t.seekg(0, std::ios::beg);
+
+  // assigner au string la valeur du fichier
+  str.assign((std::istreambuf_iterator<char>(t)),
+             std::istreambuf_iterator<char>());
+
+  // test pour voir si tout est bien chargé
+  printf("Size of str: %zu\n", str.size());
+  for (size_t i = 0; i < 64 && i < str.size(); ++i)
+    printf("%02x%s", str[i],
+           (((i + 1) % 16 == 0) ? "\n" : ((i + 1) % 2 == 0 ? " " : "")));
+  printf("\n");
+
+  // le dictionnaire, initialement vide.
+  dic_t dictionary{};
+
+  printf("Number of custom words in the dictionary: %zu\n", dictionary.size());
+
+  const auto comp_str{compress(str, dictionary)};
+
+  printf("Compressed, size of compressed string: %zu\n", comp_str.size());
+  for(const auto &c : comp_str)
+    std::cout << std::hex << c << "\t";
+  printf("Number of custom words in the dictionary: %zu\n", dictionary.size());
+
+
+
+  for(const auto &c : comp_str)
+    out << c;
+  t.close();
+  out.close();
+
   return 0;
 }