lrprefix.cpp

（1） 给定一段符合Pascal子集语法的语言

#include "StdAfx.h"
#include ".\lrprefix.h"

prefix::prefix()
{
	creation_name = -1;
	prefix_pos = -1;
}

void prefix::setPrefix(prefix *src)
{
	creation_name = src->creation_name;
	prefix_pos = src->prefix_pos;
}

int prefix::testEqual(prefix *temp)
{
	if(temp->creation_name == creation_name &&
		temp->prefix_pos == prefix_pos)
		return 1;
	return 0;
}

int prefix::isEnd()
{
	if( _creation[creation_name].getLength() == prefix_pos )
		return 1;
	return 0;
}

void prefix::output()
{
	record<<_sm.getName(_creation[creation_name].getLeft())<<" → ";
	for( int i = 0 ; i < _creation[creation_name].getLength(); i ++)
	{
		if( i == prefix_pos )
			record<<"$$";
		record<<_sm.getName(_creation[creation_name].getPosition(i))<<"  ";
	}
	if(_creation[creation_name].getLength() == prefix_pos)
		record<<" $$ ";
	record<<endl;
}

int prefix::getFirstSymbol()
{
	if( prefix_pos > _creation[creation_name].getLength() )
		return -1;
	return _creation[creation_name].getPosition(prefix_pos);
}

int prefix::getSecondSymbol()
{
	if(_creation[creation_name].getLength() == prefix_pos)//规约态
		return -1;
	if(_creation[creation_name].getLength() == prefix_pos + 1)//直接取预测符号
		return -2;
	return _creation[creation_name].getPosition(prefix_pos+1);//预测符号为符号的first集合
}

/* ---------------------------------------------------- */
/* ---------------------------------------------------- */
/* ---------------------------------------------------- */

LRPrefix::LRPrefix(void)
{
	_symbol.clear();
	symbol_num = 0;
	checked = 0;
	used = 0;
	status_in = 0;
	next = NULL;
}

int LRPrefix::testEffective()
{
	if( this->_prefix.isEnd() )
		return 0;
	return 1;
}

void LRPrefix::output()
{
	_prefix.output();
	record<<"预测符号有:";
	for(int i = 0 ;i < symbol_num ; i++)
	{
		record<<_sm.getName(_symbol[i])<<",";
	}
	record<<endl;
}

void LRPrefix::setPrefix(LRPrefix * src)
{
	//复制前缀
	_prefix.setPrefix(&src->_prefix);
		//复制预测符号
	symbol_num = src->symbol_num;
	_symbol.clear();
	for(int i = 0 ; i < src->symbol_num ; i ++)
	{
		_symbol.push_back(src->_symbol[i]);
	}
	//复制状态位置
	status_in = src->status_in;
	//复制其他
	used = src->used;
	checked = src->checked;
}

int LRPrefix::testSymbolEqual(LRPrefix *temp)
{
	for(int i = 0 ; i < symbol_num ; i++)
	{
		if( !testForwardExist(temp->_symbol[i]) )
			return 0;
	}
	return 1;
}

int LRPrefix::testEqual(LRPrefix * temp)
{
	if(temp->_prefix.testEqual(&_prefix) == 1 &&
		testSymbolEqual(temp) == 1)
		return 1;
	return 0;
}

int LRPrefix::testForwardExist(int temp)
{	
	for(int i = 0 ; i < symbol_num ; i ++)
	{
		if(temp == _symbol[i])
			return 1;
	}
	return 0;
}

void LRPrefix::addForwardSymbol(int temp)
{
	if( !testForwardExist(temp) )
	{
		_symbol.push_back(temp);
		symbol_num++;
	}
}