list.c

编译原理的词法分析模块

#include "list.h"
#include "../common.h"
#include <string.h>

void CreateList(List *list)
{
	if(list)
	{
		list->head = list->current = NULL;
		list->count = 0;
		list->currentpos = 0;
	}else
		Error("Attempt to create a list not existed.");
}

void DropList(List *list)
{
	if(list)
	{
		ListNode *p,*following;
		following = list->head;
		for(;following!=NULL;)
		{
			p = following;
			following = following->next;
			free(p);
		}
	}
	free(list);
}

void SetPosition(Position p,List *list)
{
	if(p < 0 || p >= list->count)
		Error("Attempt to set a position not in the list.");
	if(p > list->currentpos)
		for(; list->currentpos!=p; (list->currentpos)++)
			list->current = list->current->next;
	else if(p < list->currentpos)
		for(;list->currentpos!=p;(list->currentpos)--)
			list->current = list->current->previous;
	//printf("SetPosition success.\n");
}

ListNode *MakeListNode(ListEntry x)
{
	ListNode *p = (ListNode *) malloc (sizeof(ListNode));
    ListEntry px = (ListEntry) malloc (sizeof(ListEntry) + sizeof(char) * (strlen(x->value) + 1));
	if(p && px)
	{
		strcpy((char *)px.value,(char *)x.value);
        p->entry = px;
		p->next = NULL;
		p->previous = NULL;
	}else
		Error("No space for additional node can be obtained.");
	//printf("MakeListNode success.\n");
	return p;
}

void InsertListNode(Position p,ListEntry x,List *list)
{
    if(*x)
    {
	    ListNode *newnode,*following;
	    if(p < 0 || p > list->count)
    		Error("Attempt to insert in a position not in the list.");
	    else
	    {
		    newnode = MakeListNode(x);
		    if(p == 0)
		    {
    			list->head = newnode;
    			newnode->previous = NULL;
    			if(list->count == 0)
    				newnode->next == NULL;
    			else
    			{
    				SetPosition(0,list);
    				newnode->next = list->current;
    				list->current->previous = newnode;
    			}
    		}else
    		{
    			SetPosition(p-1,list);
    			following = list->current->next;
    			newnode->next = following;
    			newnode->previous = list->current;
    			list->current->next = newnode;
    			if(following)
    				following->previous = newnode;

    		}
    		list->current = newnode;
    		list->currentpos = p;
    		list->count++;
        }
    }
    //printf("InsertListNode success.\n");
}

void DeleteListNode(Position p,ListEntry x,List *list)
{
	if(p < 0 || p >= list->count)
		Error("Attempt to Delete in a position not in the list.");
	else
		SetPosition(p,list);			

    if(strlen((char *)list->current->entry) >= strlen((char *) x))
        Error("The ListEntry  memory of parameter is not enough.");
	strcpy((char *)x,(char *)list->current->entry);

	ListNode *following;
	following = list->current;

	if(list->count == 1)
	{
		list->currentpos = 0;
		list->current = list->head = NULL;
	}else
	{
		if(following->previous)
			following->previous->next = following->next;
		else
			list->head = following->next;
		if(following->next)
			following->next->previous = following->previous;

		list->currentpos = 0;
		list->current = list->head;
	}
	list->count--;
	free(following);
    //printf("DeleteListNode success.\n");
}

void RetrieveListNode(Position p,ListEntry x,List *list)
{

	if(p < 0 || p >= list->count)
		Error("Attempt to insert in a position not in the list.");
	else
		SetPosition(p,list);	

    if(strlen((char *)list->current->entry) >= strlen((char *) x))
        Error("The ListEntry  memory of parameter is not enough.");
	strcpy((char *)x,(char *)list->current->entry);
	//printf("RetrieveListNode success.\n");
}

void ReplaceList(Position p,ListEntry x,List *list)
{
	if(p < 0 || p >= list->count)
		Error("Attempt to insert in a position not in the list.");
	else
		SetPosition(p,list);
	
	ListNode *following = MakeListNode(x);
	following->next = list->current->next;
	following->previous = list->current->previous;
	if(following->previous)
		following->previous->next = following;
	if(following->next)
		following->next->previous = following;

	free(list->current);
	list->current = following;
}

void ShowListEntry(List *list)
{
	int i;
	ListNode *following;
	following = list->head;
	for(i=0;i<list->count;i++)
	{
		printf("list[%d]= %s \n",i,following->entry);
        following = following->next;
	}
}