source: trunk/yao/share/antlr-2.7.7/lib/cpp/src/InputBuffer.cpp @ 1

/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/license.html
 *
 * $Id: //depot/code/org.antlr/release/antlr-2.7.7/lib/cpp/src/InputBuffer.cpp#2 $
 */

#include "antlr/config.hpp"
#include "antlr/InputBuffer.hpp"

#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif

/** Ensure that the character buffer is sufficiently full */
void InputBuffer::fill(unsigned int amount)
{
        syncConsume();
        // Fill the buffer sufficiently to hold needed characters
        while (queue.entries() < amount + markerOffset)
        {
                // Append the next character
                queue.append(getChar());
        }
}

/** get the current lookahead characters as a string
 * @warning it may treat 0 and EOF values wrong
 */
ANTLR_USE_NAMESPACE(std)string InputBuffer::getLAChars( void ) const
{
        ANTLR_USE_NAMESPACE(std)string ret;

        for(unsigned int i = markerOffset; i < queue.entries(); i++)
                ret += queue.elementAt(i);

        return ret;
}

/** get the current marked characters as a string
 * @warning it may treat 0 and EOF values wrong
 */
ANTLR_USE_NAMESPACE(std)string InputBuffer::getMarkedChars( void ) const
{
        ANTLR_USE_NAMESPACE(std)string ret;

        for(unsigned int i = 0; i < markerOffset; i++)
                ret += queue.elementAt(i);

        return ret;
}

/** Return an integer marker that can be used to rewind the buffer to
 * its current state.
 */
unsigned int InputBuffer::mark()
{
        syncConsume();
        nMarkers++;
        return markerOffset;
}

/** Rewind the character buffer to a marker.
 * @param mark Marker returned previously from mark()
 */
void InputBuffer::rewind(unsigned int mark)
{
        syncConsume();
        markerOffset = mark;
        nMarkers--;
}

unsigned int InputBuffer::entries() const
{
        //assert(queue.entries() >= markerOffset);
        return queue.entries() - markerOffset;
}

#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif