add initial documentation

Signed-off-by: Avinal Kumar <avinal.xlvii@gmail.com>

src/Encryptor.cpp

@@ -5,11 +5,23 @@
  * @since March 06, 2021
  *
  * Encryptor class implementation
+ * The Encryptor class is a thin wrapper around Blowfish implmentation to encrypt
+ * and decrypt the file. 
  */
 
 #include "Encryptor.h"
 
 namespace krypto {
+
+/**
+ * A wrapper over Blowfish::encrypt() function to encrypt files.
+ *
+ * @param input_buf     Input char buffer
+ * @param key           Password
+ * @param in_size       Input size of the buffer
+ *
+ * @return              Size of buffer after encryption
+ */
 uint64_t Encryptor::blowfish_encrypt(std::vector<char> &input_buf,
                                      std::string const &key, uint64_t in_size) {
   uint32_t L = 0, R = 0;
@@ -36,6 +48,15 @@ uint64_t Encryptor::blowfish_encrypt(std::vector<char> &input_buf,
   return input_buf.size();
 }
 
+/**
+ * A wrapper over Blowfish::decrypt() function to decrypt files.
+ *
+ * @param input_buf     Input char buffer
+ * @param key           Password
+ * @param in_size       Input size of the buffer
+ *
+ * @return              Size of buffer after decryption
+ */
 uint64_t Encryptor::blowfish_decrypt(std::vector<char> &input_buf,
                                      std::string const &key, uint64_t in_size) {
   uint32_t L = 0, R = 0;