core/fxcrt/fx_stream.cpp

// Copyright 2017 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#include "core/fxcrt/fx_stream.h"

#include <algorithm>
#include <memory>
#include <utility>
#include <vector>

#include "core/fxcrt/fx_safe_types.h"
#include "core/fxcrt/ifxcrt_fileaccess.h"

namespace {

class CFX_CRTFileStream final : public IFX_SeekableStream {
 public:
  template <typename T, typename... Args>
  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);

  // IFX_SeekableStream:
  FX_FILESIZE GetSize() override { return m_pFile->GetSize(); }
  bool IsEOF() override { return GetPosition() >= GetSize(); }
  FX_FILESIZE GetPosition() override { return m_pFile->GetPosition(); }
  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
    return m_pFile->ReadPos(buffer, size, offset) > 0;
  }
  size_t ReadBlock(void* buffer, size_t size) override {
    return m_pFile->Read(buffer, size);
  }
  bool WriteBlock(const void* buffer,
                  FX_FILESIZE offset,
                  size_t size) override {
    return !!m_pFile->WritePos(buffer, size, offset);
  }
  bool Flush() override { return m_pFile->Flush(); }

 private:
  explicit CFX_CRTFileStream(std::unique_ptr<IFXCRT_FileAccess> pFA)
      : m_pFile(std::move(pFA)) {}
  ~CFX_CRTFileStream() override {}

  std::unique_ptr<IFXCRT_FileAccess> m_pFile;
};

}  // namespace

// static
CFX_RetainPtr<IFX_SeekableStream> IFX_SeekableStream::CreateFromFilename(
    const char* filename,
    uint32_t dwModes) {
  std::unique_ptr<IFXCRT_FileAccess> pFA = IFXCRT_FileAccess::Create();
  if (!pFA->Open(filename, dwModes))
    return nullptr;
  return pdfium::MakeRetain<CFX_CRTFileStream>(std::move(pFA));
}

// static
CFX_RetainPtr<IFX_SeekableStream> IFX_SeekableStream::CreateFromFilename(
    const wchar_t* filename,
    uint32_t dwModes) {
  std::unique_ptr<IFXCRT_FileAccess> pFA = IFXCRT_FileAccess::Create();
  if (!pFA->Open(filename, dwModes))
    return nullptr;
  return pdfium::MakeRetain<CFX_CRTFileStream>(std::move(pFA));
}

// static
CFX_RetainPtr<IFX_SeekableReadStream>
IFX_SeekableReadStream::CreateFromFilename(const char* filename) {
  return IFX_SeekableStream::CreateFromFilename(filename, FX_FILEMODE_ReadOnly);
}

bool IFX_SeekableWriteStream::WriteBlock(const void* pData, size_t size) {
  return WriteBlock(pData, GetSize(), size);
}

bool IFX_SeekableReadStream::IsEOF() {
  return false;
}

FX_FILESIZE IFX_SeekableReadStream::GetPosition() {
  return 0;
}

size_t IFX_SeekableReadStream::ReadBlock(void* buffer, size_t size) {
  return 0;
}

bool IFX_SeekableStream::WriteBlock(const void* buffer, size_t size) {
  return WriteBlock(buffer, GetSize(), size);
}

bool IFX_SeekableStream::WriteString(const CFX_ByteStringC& str) {
  return WriteBlock(str.c_str(), str.GetLength());
}