New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/coding/file_writer.hpp

@@ -0,0 +1,96 @@
+#pragma once
+
+#include "coding/writer.hpp"
+#include "coding/internal/file_data.hpp"
+#include "coding/write_to_sink.hpp"
+
+#include "base/assert.hpp"
+#include "base/macros.hpp"
+
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <string>
+
+// FileWriter, not thread safe.
+class FileWriter : public Writer
+{
+  DISALLOW_COPY(FileWriter);
+
+public:
+  // Values actually match internal FileData::Op enum.
+  enum Op
+  {
+    // Create an empty file for writing. If a file with the same name already exists
+    // its content is erased and the file is treated as a new empty file.
+    OP_WRITE_TRUNCATE = 1,
+
+    // Open a file for update. The file is created if it does not exist.
+    OP_WRITE_EXISTING = 2,
+
+    // Append to a file. Writing operations append data at the end of the file.
+    // The file is created if it does not exist.
+    // Seek should not be called, if file is opened for append.
+    OP_APPEND = 3
+  };
+
+  explicit FileWriter(std::string const & fileName,
+                      Op operation = OP_WRITE_TRUNCATE);
+  FileWriter(FileWriter && rhs) = default;
+
+  virtual ~FileWriter() noexcept(false);
+
+  // Writer overrides:
+  void Seek(uint64_t pos) override;
+  uint64_t Pos() const override;
+  void Write(void const * p, size_t size) override;
+
+  virtual uint64_t Size() const;
+  virtual void Flush() noexcept(false);
+
+  std::string const & GetName() const;
+
+  static void DeleteFileX(std::string const & fName);
+
+protected:
+  std::unique_ptr<base::FileData> m_pFileData;
+};
+
+class FilesContainerWriter : public FileWriter
+{
+public:
+  FilesContainerWriter(std::string const & fileName, Op operation)
+    : FileWriter(fileName, operation)
+  {
+  }
+
+  void WritePaddingByEnd(size_t factor) { WritePadding(Size(), factor); }
+  void WritePaddingByPos(size_t factor) { WritePadding(Pos(), factor); }
+
+private:
+  void WritePadding(uint64_t offset, uint64_t factor)
+  {
+    ASSERT_GREATER(factor, 1, ());
+    uint64_t const padding = ((offset + factor - 1) / factor) * factor - offset;
+    if (padding == 0)
+      return;
+    WriteZeroesToSink(*this, padding);
+  }
+};
+
+class TruncatingFileWriter : public FilesContainerWriter
+{
+public:
+  explicit TruncatingFileWriter(std::string const & fileName)
+    : FilesContainerWriter(fileName, FileWriter::OP_WRITE_EXISTING)
+  {
+  }
+
+  TruncatingFileWriter(TruncatingFileWriter && rhs) = default;
+
+  ~TruncatingFileWriter() noexcept(false) override
+  {
+    m_pFileData->Flush();
+    m_pFileData->Truncate(Pos());
+  }
+};