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, 2017-2019 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// Copyright (C) 2019 Adam Reichold <adam.reichold@t-online.de>
21//
22// To see a description of the changes please see the Changelog file that
23// came with your tarball or type make ChangeLog if you are building from git
24//
25//========================================================================
26
27#ifndef LEXER_H
28#define LEXER_H
29
30#include "Object.h"
31#include "Stream.h"
32
33class XRef;
34
35#define tokBufSize 128 // size of token buffer
36
37//------------------------------------------------------------------------
38// Lexer
39//------------------------------------------------------------------------
40
41class POPPLER_PRIVATE_EXPORT Lexer
42{
43public:
44 // Construct a lexer for a single stream. Deletes the stream when
45 // lexer is deleted.
46 Lexer(XRef *xrefA, Stream *str);
47
48 // Construct a lexer for a stream or array of streams (assumes obj
49 // is either a stream or array of streams).
50 Lexer(XRef *xrefA, Object *obj);
51
52 // Destructor.
53 ~Lexer();
54
55 Lexer(const Lexer &) = delete;
56 Lexer &operator=(const Lexer &) = delete;
57
58 // Get the next object from the input stream.
59 Object getObj(int objNum = -1);
60 Object getObj(const char *cmdA, int objNum);
61 template<typename T>
62 Object getObj(T) = delete;
63
64 // Skip to the beginning of the next line in the input stream.
65 void skipToNextLine();
66
67 // Skip over one character.
68 void skipChar() { getChar(); }
69
70 // Get stream.
71 Stream *getStream() { return curStr.isStream() ? curStr.getStream() : nullptr; }
72
73 // Get current position in file. This is only used for error
74 // messages.
75 Goffset getPos() const { return curStr.isStream() ? curStr.getStream()->getPos() : -1; }
76
77 // Set position in file.
78 void setPos(Goffset pos)
79 {
80 if (curStr.isStream()) {
81 curStr.getStream()->setPos(pos);
82 }
83 }
84
85 // Returns true if <c> is a whitespace character.
86 static bool isSpace(int c);
87
88 // often (e.g. ~30% on PDF Refernce 1.6 pdf file from Adobe site) getChar
89 // is called right after lookChar. In order to avoid expensive re-doing
90 // getChar() of underlying stream, we cache the last value found by
91 // lookChar() in lookCharLastValueCached. A special value
92 // LOOK_VALUE_NOT_CACHED that should never be part of stream indicates
93 // that no value was cached
94 static const int LOOK_VALUE_NOT_CACHED = -3;
95 int lookCharLastValueCached;
96
97 XRef *getXRef() const { return xref; }
98 bool hasXRef() const { return xref != nullptr; }
99
100private:
101 int getChar(bool comesFromLook = false);
102 int lookChar();
103
104 Array *streams; // array of input streams
105 int strPtr; // index of current stream
106 Object curStr; // current stream
107 bool freeArray; // should lexer free the streams array?
108 char tokBuf[tokBufSize]; // temporary token buffer
109
110 XRef *xref;
111};
112
113#endif
114

source code of poppler/poppler/Lexer.h