source/libs/poppler/poppler-src/poppler/Lexer.h

   1 //========================================================================
   2 //
   3 // Lexer.h
   4 //
   5 // Copyright 1996-2003 Glyph & Cog, LLC
   6 //
   7 //========================================================================
   8
   9 //========================================================================
  10 //
  11 // Modified under the Poppler project - http://poppler.freedesktop.org
  12 //
  13 // All changes made under the Poppler project to this file are licensed
  14 // under GPL version 2 or later
  15 //
  16 // Copyright (C) 2006, 2007, 2010, 2013 Albert Astals Cid <aacid@kde.org>
  17 // Copyright (C) 2006 Krzysztof Kowalczyk <kkowalczyk@gmail.com>
  18 // Copyright (C) 2013 Adrian Johnson <ajohnson@redneon.com>
  19 // Copyright (C) 2013 Thomas Freitag <Thomas.Freitag@alfa.de>
  20 //
  21 // To see a description of the changes please see the Changelog file that
  22 // came with your tarball or type make ChangeLog if you are building from git
  23 //
  24 //========================================================================
  25
  26 #ifndef LEXER_H
  27 #define LEXER_H
  28
  29 #ifdef USE_GCC_PRAGMAS
  30 #pragma interface
  31 #endif
  32
  33 #include "Object.h"
  34 #include "Stream.h"
  35
  36 class XRef;
  37
  38 #define tokBufSize 128          // size of token buffer
  39
  40 //------------------------------------------------------------------------
  41 // Lexer
  42 //------------------------------------------------------------------------
  43
  44 class Lexer {
  45 public:
  46
  47   // Construct a lexer for a single stream.  Deletes the stream when
  48   // lexer is deleted.
  49   Lexer(XRef *xrefA, Stream *str);
  50
  51   // Construct a lexer for a stream or array of streams (assumes obj
  52   // is either a stream or array of streams).
  53   Lexer(XRef *xrefA, Object *obj);
  54
  55   // Destructor.
  56   ~Lexer();
  57
  58   // Get the next object from the input stream.
  59   Object *getObj(Object *obj, int objNum = -1);
  60   Object *getObj(Object *obj, const char *cmdA, int objNum);
  61
  62   // Skip to the beginning of the next line in the input stream.
  63   void skipToNextLine();
  64
  65   // Skip over one character.
  66   void skipChar() { getChar(); }
  67
  68   // Get stream.
  69   Stream *getStream()
  70     { return curStr.isStream() ? curStr.getStream() : (Stream *)NULL; }
  71
  72   // Get current position in file.  This is only used for error
  73   // messages.
  74   Goffset getPos()
  75     { return curStr.isStream() ? curStr.streamGetPos() : -1; }
  76
  77   // Set position in file.
  78   void setPos(Goffset pos, int dir = 0)
  79     { if (curStr.isStream()) curStr.streamSetPos(pos, dir); }
  80
  81   // Returns true if <c> is a whitespace character.
  82   static GBool isSpace(int c);
  83
  84
  85   // often (e.g. ~30% on PDF Refernce 1.6 pdf file from Adobe site) getChar
  86   // is called right after lookChar. In order to avoid expensive re-doing
  87   // getChar() of underlying stream, we cache the last value found by
  88   // lookChar() in lookCharLastValueCached. A special value
  89   // LOOK_VALUE_NOT_CACHED that should never be part of stream indicates
  90   // that no value was cached
  91   static const int LOOK_VALUE_NOT_CACHED = -3;
  92   int lookCharLastValueCached;
  93
  94 private:
  95
  96   int getChar(GBool comesFromLook = gFalse);
  97   int lookChar();
  98
  99   Array *streams;               // array of input streams
 100   int strPtr;                   // index of current stream
 101   Object curStr;                // current stream
 102   GBool freeArray;              // should lexer free the streams array?
 103   char tokBuf[tokBufSize];      // temporary token buffer
 104
 105   XRef *xref;
 106 };
 107
 108 #endif