fix: update NlpCodec

NlpCodec/NlpCodec.cpp

@@ -13,6 +13,8 @@
 
 namespace NlpCodec {
 
+#pragma region Help Structs and Functions
+
     /// @brief NlpCodec universal exception.
     /// @details Once this exception was thrown, it means that somethings went wrong.
     /// and main function should catch it, output error message and exit program immediately.
@@ -32,12 +34,29 @@ namespace NlpCodec {
     static constexpr _TyTo SafeCast(_TyFrom value) {
         if (!std::in_range<_TyTo>(value))
             throw NlpException(
-                    "Fail to cast integral number because given value is greater than container. "
+                    "Fail to cast integral number because given value is greater than the type can hold. "
                     "This is usually caused by your input or output file is too long.");
         return static_cast<_TyTo>(value);
     }
 
-#pragma region "Encryption Stuff" {
+    /// @brief The safe version of `std::ifstream::read`.
+    /// Throw exception if fail to read.
+    static void SafeRead(std::ifstream& fin, char* s, std::streamsize count) {
+        fin.read(s, count);
+        if (!fin.good() || fin.gcount() != count)
+            throw NlpException("Fail to read data from file.");
+    }
+    /// @brief The safe version of `std::ofstream::write`.
+    /// Throw exception if fail to write.
+    static void SafeWrite(std::ofstream& fout, const char* s, std::streamsize count) {
+        fout.write(s, count);
+        if (!fout.good())
+            throw NlpException("Fail to write data into file.");
+    }
+
+#pragma endregion
+
+#pragma region Encryption Stuff
 
     /*
 
@@ -155,7 +174,7 @@ namespace NlpCodec {
         }
     }
 
-#pragma endregion }
+#pragma endregion
 
     /// @brief Get the length of given file stream.
     static uint32_t GetFileLength(std::ifstream& fin) {
@@ -195,9 +214,7 @@ namespace NlpCodec {
             throw NlpException("Fail to allocate memory.");
 
         // Read data from file to input buffer
-        fin.read(inbuf.get(), raw_size);
+        SafeRead(fin, inbuf.get(), raw_size);
-        if (!fin.good() || fin.gcount() != raw_size)
-            throw NlpException("Fail to read file data into buffer.");
 
         // Do XOR operation
         CircularXorOperation(inbuf.get(), raw_size);
@@ -209,9 +226,9 @@ namespace NlpCodec {
             reinterpret_cast<Bytef*>(inbuf.get()), static_cast<uLong>(raw_size),
             Z_BEST_COMPRESSION
         );
-        // Check ZLib result.
+        // Check zlib result.
         if (ret != Z_OK)
-            throw NlpException("Zlib compress() failed.");
+            throw NlpException("zlib compress() failed.");
         // Fetch final compressed size.
         uint32_t compressed_size = SafeCast<uint32_t>(dest_len);
 
@@ -219,21 +236,15 @@ namespace NlpCodec {
         uint32_t checksum = static_cast<uint32_t>(adler32(0u, reinterpret_cast<Bytef*>(outbuf.get()), SafeCast<uInt>(compressed_size)));
 
         // Write compressed data into file
-        fout.write(outbuf.get(), compressed_size);
+        SafeWrite(fout, outbuf.get(), compressed_size);
-        if (!fout.good())
-            throw NlpException("Fail to write data into file.");
 
         // Raw size and checksum need some extra encryption before writting
         raw_size = EncryptRawFileLength(raw_size);
         checksum = EncryptChecksum(checksum);
 
         // Write raw size and checksum
-        fout.write(reinterpret_cast<char*>(&raw_size), sizeof(uint32_t));
+        SafeWrite(fout, reinterpret_cast<char*>(&raw_size), sizeof(uint32_t));
-        if (!fout.good())
+        SafeWrite(fout, reinterpret_cast<char*>(&checksum), sizeof(uint32_t));
-            throw NlpException("Fail to write raw size into file.");
-        fout.write(reinterpret_cast<char*>(&checksum), sizeof(uint32_t));
-        if (!fout.good())
-            throw NlpException("Fail to write checksum into file.");
 
     }
 
@@ -247,8 +258,8 @@ namespace NlpCodec {
         compressed_size -= TAIL_SIZE;
         fin.seekg(compressed_size, std::ios_base::beg);
         uint32_t expected_raw_size = 0u, expected_checksum = 0u;
-        fin.read(reinterpret_cast<char*>(&expected_raw_size), sizeof(uint32_t));
+        SafeRead(fin, reinterpret_cast<char*>(&expected_raw_size), sizeof(uint32_t));
-        fin.read(reinterpret_cast<char*>(&expected_checksum), sizeof(uint32_t));
+        SafeRead(fin, reinterpret_cast<char*>(&expected_checksum), sizeof(uint32_t));
         fin.seekg(0, std::ios_base::beg);
 
         // Raw size and checksum data need to do some extra decryption.
@@ -262,9 +273,7 @@ namespace NlpCodec {
             throw NlpException("Fail to allocate memory.");
 
         // Read file into buffer
-        fin.read(inbuf.get(), compressed_size);
+        SafeRead(fin, inbuf.get(), compressed_size);
-        if (!fin.good() || fin.gcount() != compressed_size)
-            throw NlpException("Fail to read data into buffer.\n");
 
         // Test checksum
         uint32_t checksum = static_cast<uint32_t>(adler32(0u, reinterpret_cast<Bytef*>(inbuf.get()), SafeCast<uInt>(compressed_size)));
@@ -281,15 +290,13 @@ namespace NlpCodec {
         );
         // Check zlib result
         if (ret != Z_OK)
-            throw NlpException("Zlib uncompress() failed.");
+            throw NlpException("zlib uncompress() failed.");
 
-        // do xor operation
+        // Do XOR operation
         CircularXorOperation(outbuf.get(), expected_raw_size);
 
         // Write result into file
-        fout.write(outbuf.get(), expected_raw_size);
+        SafeWrite(fout, outbuf.get(), expected_raw_size);
-        if (!fout.good())
-            throw NlpException("Fail to write data into file.");
 
     }
 
@@ -321,11 +328,11 @@ namespace NlpCodec::Runtime {
                 << "encode  - encode text file into NLP file." << std::endl
                 << "decode  - decode NLP file into text file." << std::endl
                 << "<src>   - the source file." << std::endl
-                << "        the path to text file in encode mode." << std::endl
+                << "          encode mode: the path to text file." << std::endl
-                << "        the path to NLP file in decode mode." << std::endl
+                << "          decode mode: the path to NLP file." << std::endl
                 << "<dest>  - the destination file." << std::endl
-                << "         the path to NLP file in encode mode." << std::endl
+                << "          encode mode: the path to NLP file." << std::endl
-                << "         the path to text file in decode mode." << std::endl
+                << "          decode mode: the path to text file." << std::endl
                 << "" << std::endl;
     }