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      1 // Copyright 2016 PDFium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
      6 
      7 #ifndef CORE_FPDFAPI_PARSER_CPDF_SYNTAX_PARSER_H_
      8 #define CORE_FPDFAPI_PARSER_CPDF_SYNTAX_PARSER_H_
      9 
     10 #include <memory>
     11 
     12 #include "core/fxcrt/cfx_string_pool_template.h"
     13 #include "core/fxcrt/cfx_weak_ptr.h"
     14 #include "core/fxcrt/fx_basic.h"
     15 
     16 class CPDF_CryptoHandler;
     17 class CPDF_Dictionary;
     18 class CPDF_IndirectObjectHolder;
     19 class CPDF_Object;
     20 class CPDF_Stream;
     21 class IFX_SeekableReadStream;
     22 
     23 class CPDF_SyntaxParser {
     24  public:
     25   CPDF_SyntaxParser();
     26   explicit CPDF_SyntaxParser(const CFX_WeakPtr<CFX_ByteStringPool>& pPool);
     27   ~CPDF_SyntaxParser();
     28 
     29   void InitParser(const CFX_RetainPtr<IFX_SeekableReadStream>& pFileAccess,
     30                   uint32_t HeaderOffset);
     31 
     32   FX_FILESIZE SavePos() const { return m_Pos; }
     33   void RestorePos(FX_FILESIZE pos) { m_Pos = pos; }
     34 
     35   std::unique_ptr<CPDF_Object> GetObject(CPDF_IndirectObjectHolder* pObjList,
     36                                          uint32_t objnum,
     37                                          uint32_t gennum,
     38                                          bool bDecrypt);
     39 
     40   std::unique_ptr<CPDF_Object> GetObjectForStrict(
     41       CPDF_IndirectObjectHolder* pObjList,
     42       uint32_t objnum,
     43       uint32_t gennum);
     44 
     45   CFX_ByteString GetKeyword();
     46   void ToNextLine();
     47   void ToNextWord();
     48   bool SearchWord(const CFX_ByteStringC& word,
     49                   bool bWholeWord,
     50                   bool bForward,
     51                   FX_FILESIZE limit);
     52 
     53   FX_FILESIZE FindTag(const CFX_ByteStringC& tag, FX_FILESIZE limit);
     54   void SetEncrypt(std::unique_ptr<CPDF_CryptoHandler> pCryptoHandler);
     55   bool ReadBlock(uint8_t* pBuf, uint32_t size);
     56   bool GetCharAt(FX_FILESIZE pos, uint8_t& ch);
     57   CFX_ByteString GetNextWord(bool* bIsNumber);
     58 
     59  private:
     60   friend class CPDF_Parser;
     61   friend class CPDF_DataAvail;
     62   friend class cpdf_syntax_parser_ReadHexString_Test;
     63 
     64   static const int kParserMaxRecursionDepth = 64;
     65   static int s_CurrentRecursionDepth;
     66 
     67   uint32_t GetDirectNum();
     68   bool ReadChar(FX_FILESIZE read_pos, uint32_t read_size);
     69   bool GetNextChar(uint8_t& ch);
     70   bool GetCharAtBackward(FX_FILESIZE pos, uint8_t& ch);
     71   void GetNextWordInternal(bool* bIsNumber);
     72   bool IsWholeWord(FX_FILESIZE startpos,
     73                    FX_FILESIZE limit,
     74                    const CFX_ByteStringC& tag,
     75                    bool checkKeyword);
     76 
     77   CFX_ByteString ReadString();
     78   CFX_ByteString ReadHexString();
     79   unsigned int ReadEOLMarkers(FX_FILESIZE pos);
     80   std::unique_ptr<CPDF_Stream> ReadStream(
     81       std::unique_ptr<CPDF_Dictionary> pDict,
     82       uint32_t objnum,
     83       uint32_t gennum);
     84 
     85   inline bool CheckPosition(FX_FILESIZE pos) {
     86     return m_BufOffset >= pos ||
     87            static_cast<FX_FILESIZE>(m_BufOffset + m_BufSize) <= pos;
     88   }
     89 
     90   FX_FILESIZE m_Pos;
     91   uint32_t m_MetadataObjnum;
     92   CFX_RetainPtr<IFX_SeekableReadStream> m_pFileAccess;
     93   FX_FILESIZE m_HeaderOffset;
     94   FX_FILESIZE m_FileLen;
     95   uint8_t* m_pFileBuf;
     96   uint32_t m_BufSize;
     97   FX_FILESIZE m_BufOffset;
     98   std::unique_ptr<CPDF_CryptoHandler> m_pCryptoHandler;
     99   uint8_t m_WordBuffer[257];
    100   uint32_t m_WordSize;
    101   CFX_WeakPtr<CFX_ByteStringPool> m_pPool;
    102 };
    103 
    104 #endif  // CORE_FPDFAPI_PARSER_CPDF_SYNTAX_PARSER_H_
    105