cpdf_stream.h

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// Copyright 2016 The PDFium Authors
// 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_FPDFAPI_PARSER_CPDF_STREAM_H_
#define CORE_FPDFAPI_PARSER_CPDF_STREAM_H_
 
#include <stdint.h>
 
#include <memory>
#include <set>
 
#include "core/fpdfapi/parser/cpdf_object.h"
#include "core/fxcrt/data_vector.h"
#include "core/fxcrt/fx_string_wrappers.h"
#include "core/fxcrt/retain_ptr.h"
#include "third_party/abseil-cpp/absl/types/variant.h"
 
class IFX_SeekableReadStream;
 
class CPDF_Stream final : public CPDF_Object {
 public:
  static constexpr int kFileBufSize = 512;
 
  CONSTRUCT_VIA_MAKE_RETAIN;
 
  // CPDF_Object:
  Type GetType() const override;
  RetainPtr<CPDF_Object> Clone() const override;
  WideString GetUnicodeText() const override;
  CPDF_Stream* AsMutableStream() override;
  bool WriteTo(IFX_ArchiveStream* archive,
               const CPDF_Encryptor* encryptor) const override;
 
  size_t GetRawSize() const;
  // Can only be called when stream is memory-based.
  // This is meant to be used by CPDF_StreamAcc only.
  // Other callers should use CPDF_StreamAcc to access data in all cases.
  pdfium::span<const uint8_t> GetInMemoryRawData() const;
 
  // Copies span or stream into internally-owned buffer.
  void SetData(pdfium::span<const uint8_t> pData);
  void SetDataFromStringstream(fxcrt::ostringstream* stream);
 
  void TakeData(DataVector<uint8_t> data);
 
  // Set data and remove "Filter" and "DecodeParms" fields from stream
  // dictionary. Copies span or stream into internally-owned buffer.
  void SetDataAndRemoveFilter(pdfium::span<const uint8_t> pData);
  void SetDataFromStringstreamAndRemoveFilter(fxcrt::ostringstream* stream);
 
  void InitStreamFromFile(RetainPtr<IFX_SeekableReadStream> file);
 
  // Can only be called when a stream is not memory-based.
  DataVector<uint8_t> ReadAllRawData() const;
 
  bool IsFileBased() const {
    return absl::holds_alternative<RetainPtr<IFX_SeekableReadStream>>(data_);
  }
  bool IsMemoryBased() const {
    return absl::holds_alternative<DataVector<uint8_t>>(data_);
  }
  bool HasFilter() const;
 
 private:
  friend class CPDF_Dictionary;
 
  // Initializes with empty data and /Length set to 0 in `dict`.
  // `dict` must be non-null and be a direct object.
  explicit CPDF_Stream(RetainPtr<CPDF_Dictionary> dict);
 
  // Copies `span` and `stream`, respectively. Creates a new dictionary with the
  // /Length set.
  explicit CPDF_Stream(pdfium::span<const uint8_t> span);
  explicit CPDF_Stream(fxcrt::ostringstream* stream);
 
  // Reads data from `file`. `dict` will have its /Length set based on `file`.
  // `dict` must be non-null and be a direct object.
  CPDF_Stream(RetainPtr<IFX_SeekableReadStream> file,
              RetainPtr<CPDF_Dictionary> dict);
 
  // Takes `data`.
  // `dict` must be non-null and be a direct object.
  CPDF_Stream(DataVector<uint8_t> data, RetainPtr<CPDF_Dictionary> dict);
  ~CPDF_Stream() override;
 
  const CPDF_Dictionary* GetDictInternal() const override;
  RetainPtr<CPDF_Object> CloneNonCyclic(
      bool bDirect,
      std::set<const CPDF_Object*>* pVisited) const override;
 
  void SetLengthInDict(int length);
 
  absl::variant<RetainPtr<IFX_SeekableReadStream>, DataVector<uint8_t>> data_;
  RetainPtr<CPDF_Dictionary> dict_;
};
 
inline CPDF_Stream* ToStream(CPDF_Object* obj) {
  return obj ? obj->AsMutableStream() : nullptr;
}
 
inline const CPDF_Stream* ToStream(const CPDF_Object* obj) {
  return obj ? obj->AsStream() : nullptr;
}
 
inline RetainPtr<CPDF_Stream> ToStream(RetainPtr<CPDF_Object> obj) {
  return RetainPtr<CPDF_Stream>(ToStream(obj.Get()));
}
 
inline RetainPtr<const CPDF_Stream> ToStream(RetainPtr<const CPDF_Object> obj) {
  return RetainPtr<const CPDF_Stream>(ToStream(obj.Get()));
}
 
#endif  // CORE_FPDFAPI_PARSER_CPDF_STREAM_H_