1  /* ANTLR Translator Generator
 2   * Project led by Terence Parr at http://www.jGuru.com
 3   * Software rights: http://www.antlr.org/license.html
 4   *
 5   * $Id: //depot/code/org.antlr/release/antlr-2.7.7/lib/cpp/src/InputBuffer.cpp#2 $
 6   */
 7  
 8  #include "antlr/config.hpp"
 9  #include "antlr/InputBuffer.hpp"
10  
11  #ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
12  namespace antlr {
13  #endif
14  
15  /** Ensure that the character buffer is sufficiently full */
16  void InputBuffer::fill(unsigned int amount)
17  {
18  	syncConsume();
19  	// Fill the buffer sufficiently to hold needed characters
20  	while (queue.entries() < amount + markerOffset)
21  	{
22  		// Append the next character
23  		queue.append(getChar());
24  	}
25  }
26  
27  /** get the current lookahead characters as a string
28   * @warning it may treat 0 and EOF values wrong
29   */
30  ANTLR_USE_NAMESPACE(std)string InputBuffer::getLAChars( void ) const
31  {
32  	ANTLR_USE_NAMESPACE(std)string ret;
33  
34  	for(unsigned int i = markerOffset; i < queue.entries(); i++)
35  		ret += queue.elementAt(i);
36  
37  	return ret;
38  }
39  
40  /** get the current marked characters as a string
41   * @warning it may treat 0 and EOF values wrong
42   */
43  ANTLR_USE_NAMESPACE(std)string InputBuffer::getMarkedChars( void ) const
44  {
45  	ANTLR_USE_NAMESPACE(std)string ret;
46  
47  	for(unsigned int i = 0; i < markerOffset; i++)
48  		ret += queue.elementAt(i);
49  
50  	return ret;
51  }
52  
53  /** Return an integer marker that can be used to rewind the buffer to
54   * its current state.
55   */
56  unsigned int InputBuffer::mark()
57  {
58  	syncConsume();
59  	nMarkers++;
60  	return markerOffset;
61  }
62  
63  /** Rewind the character buffer to a marker.
64   * @param mark Marker returned previously from mark()
65   */
66  void InputBuffer::rewind(unsigned int mark)
67  {
68  	syncConsume();
69  	markerOffset = mark;
70  	nMarkers--;
71  }
72  
73  unsigned int InputBuffer::entries() const
74  {
75  	//assert(queue.entries() >= markerOffset);
76  	return (unsigned int)queue.entries() - markerOffset;
77  }
78  
79  #ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
80  }
81  #endif