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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_PAGE_CPDF_PSENGINE_H_
      8 #define CORE_FPDFAPI_PAGE_CPDF_PSENGINE_H_
      9 
     10 #include <memory>
     11 #include <vector>
     12 
     13 #include "core/fxcrt/fx_string.h"
     14 #include "core/fxcrt/fx_system.h"
     15 
     16 class CPDF_PSEngine;
     17 class CPDF_PSProc;
     18 class CPDF_SimpleParser;
     19 
     20 enum PDF_PSOP : uint8_t {
     21   PSOP_ADD,
     22   PSOP_SUB,
     23   PSOP_MUL,
     24   PSOP_DIV,
     25   PSOP_IDIV,
     26   PSOP_MOD,
     27   PSOP_NEG,
     28   PSOP_ABS,
     29   PSOP_CEILING,
     30   PSOP_FLOOR,
     31   PSOP_ROUND,
     32   PSOP_TRUNCATE,
     33   PSOP_SQRT,
     34   PSOP_SIN,
     35   PSOP_COS,
     36   PSOP_ATAN,
     37   PSOP_EXP,
     38   PSOP_LN,
     39   PSOP_LOG,
     40   PSOP_CVI,
     41   PSOP_CVR,
     42   PSOP_EQ,
     43   PSOP_NE,
     44   PSOP_GT,
     45   PSOP_GE,
     46   PSOP_LT,
     47   PSOP_LE,
     48   PSOP_AND,
     49   PSOP_OR,
     50   PSOP_XOR,
     51   PSOP_NOT,
     52   PSOP_BITSHIFT,
     53   PSOP_TRUE,
     54   PSOP_FALSE,
     55   PSOP_IF,
     56   PSOP_IFELSE,
     57   PSOP_POP,
     58   PSOP_EXCH,
     59   PSOP_DUP,
     60   PSOP_COPY,
     61   PSOP_INDEX,
     62   PSOP_ROLL,
     63   PSOP_PROC,
     64   PSOP_CONST
     65 };
     66 
     67 class CPDF_PSOP {
     68  public:
     69   CPDF_PSOP();
     70   explicit CPDF_PSOP(PDF_PSOP op);
     71   explicit CPDF_PSOP(float value);
     72   ~CPDF_PSOP();
     73 
     74   float GetFloatValue() const;
     75   CPDF_PSProc* GetProc() const;
     76   PDF_PSOP GetOp() const { return m_op; }
     77 
     78  private:
     79   const PDF_PSOP m_op;
     80   const float m_value;
     81   std::unique_ptr<CPDF_PSProc> m_proc;
     82 };
     83 
     84 class CPDF_PSProc {
     85  public:
     86   CPDF_PSProc();
     87   ~CPDF_PSProc();
     88 
     89   bool Parse(CPDF_SimpleParser* parser, int depth);
     90   bool Execute(CPDF_PSEngine* pEngine);
     91 
     92   // These methods are exposed for testing.
     93   void AddOperatorForTesting(const ByteStringView& word);
     94   size_t num_operators() const { return m_Operators.size(); }
     95   const std::unique_ptr<CPDF_PSOP>& last_operator() {
     96     return m_Operators.back();
     97   }
     98 
     99  private:
    100   static const int kMaxDepth = 128;
    101 
    102   void AddOperator(const ByteStringView& word);
    103 
    104   std::vector<std::unique_ptr<CPDF_PSOP>> m_Operators;
    105 };
    106 
    107 class CPDF_PSEngine {
    108  public:
    109   CPDF_PSEngine();
    110   ~CPDF_PSEngine();
    111 
    112   bool Parse(const char* str, int size);
    113   bool Execute();
    114   bool DoOperator(PDF_PSOP op);
    115   void Reset() { m_StackCount = 0; }
    116   void Push(float value);
    117   float Pop();
    118   int PopInt();
    119   uint32_t GetStackSize() const { return m_StackCount; }
    120 
    121  private:
    122   static constexpr uint32_t kPSEngineStackSize = 100;
    123   float m_Stack[kPSEngineStackSize];
    124   uint32_t m_StackCount;
    125   CPDF_PSProc m_MainProc;
    126 };
    127 
    128 #endif  // CORE_FPDFAPI_PAGE_CPDF_PSENGINE_H_
    129