text: // 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
  
  #ifndef CORE_FXCRT_CFX_BINARYBUF_H_
  #define CORE_FXCRT_CFX_BINARYBUF_H_
  
  #include <memory>
  
  #include "core/fxcrt/fx_memory_wrappers.h"
  #include "core/fxcrt/fx_string.h"
  #include "core/fxcrt/fx_system.h"
  #include "third_party/base/span.h"
  
  class CFX_BinaryBuf {
   public:
    CFX_BinaryBuf();
    CFX_BinaryBuf(CFX_BinaryBuf&& that) noexcept;
    virtual ~CFX_BinaryBuf();
  
    // Moved-from value will be left empty.
    CFX_BinaryBuf& operator=(CFX_BinaryBuf&& that) noexcept;
  
    pdfium::span<uint8_t> GetSpan();
    pdfium::span<const uint8_t> GetSpan() const;
    uint8_t* GetBuffer() const { return m_pBuffer.get(); }
    size_t GetSize() const { return m_DataSize; }
    virtual size_t GetLength() const;
    bool IsEmpty() const { return GetLength() == 0; }
  
    void Clear();
    void SetAllocStep(size_t step) { m_AllocStep = step; }
    void EstimateSize(size_t size);
    void AppendSpan(pdfium::span<const uint8_t> span);
    void AppendBlock(const void* pBuf, size_t size);
    void AppendString(const ByteString& str) {
      AppendBlock(str.c_str(), str.GetLength());
    }
  
    void AppendByte(uint8_t byte) {
      ExpandBuf(1);
      m_pBuffer.get()[m_DataSize++] = byte;
    }
  
    void Delete(size_t start_index, size_t count);
  
    // Releases ownership of |m_pBuffer| and returns it.
    std::unique_ptr<uint8_t, FxFreeDeleter> DetachBuffer();
  
   protected:
    void ExpandBuf(size_t size);
  
    size_t m_AllocStep = 0;
    size_t m_AllocSize = 0;
    size_t m_DataSize = 0;
    std::unique_ptr<uint8_t, FxFreeDeleter> m_pBuffer;
  };
  
  #endif  // CORE_FXCRT_CFX_BINARYBUF_H_
  