circlequeue.cpp

这是一个linux下的Shell.有命令历史和命令提示

#include <unistd.h>
#include <fcntl.h>
#include "CircleQueue.h"

CircleQueue::CircleQueue(int size)
{
	num  = size;
	cur  = tail = head = 0;
	num_cur = 0;
}
char* CircleQueue::getCur(void)
{
	if(cur)
	{
		char* o = new char[strlen(cur->ptr)+1];
		strcpy(o,cur->ptr);
		return o;
	}
	return 0;
}

void CircleQueue::incCur(void)
{
	if(cur)
		cur = (cur==head)?tail:cur->pre;
}

void CircleQueue::devCur(void)
{
	if(cur)
		cur = (cur==tail)?head:cur->next;
}
void CircleQueue::inset(char* p)
{
	if(!head)
		cur = tail = head = new Node_Queue(p,0,0);	
	else if(tail == head)
		head->next = tail->pre = cur = head = head->inset(p);
	else
		cur = head = head->inset(p);	
	
	
	num_cur++;
	if(num_cur > num )
		del();
}
void CircleQueue::initffile(char* filepath)
{
	head = 0;
	cur = 0;
	
	if(!filepath)
		return;
	int fid = open(filepath,O_RDONLY);
	if(fid >= 0)
	{
		struct stat fileinfo;
		fstat(fid,&fileinfo);
		
		int SIZE = fileinfo.st_size;
		char a;
		int start = 0;
		do
		{
			read(fid,&a,1);
			start++;
		}while(a!='\n');

		for(int i = start;i < (SIZE - 1); i++)
		{
			read(fid,&a,1);
			if(a == '\n')
			{
				lseek(fid,start,SEEK_SET);
				char* work = new char[i - start + 1];
				read(fid,work,i - start + 1);
				work[i - start] = 0;
				inset(work);
				start = i+1;
			}	
		}
		close(fid);
	}
}


void CircleQueue::del(void)
{
	if(tail)
	{
		tail = tail->del();	
		num_cur--;
	}
	if(!num_cur)
		cur=head=0;
}

void  CircleQueue::setSize(int size)
{
	if(size <= 0)						//If size <= 0, I will clear the CircleQueue.
	{
		for(int i = 0; i < num_cur;i++)
			del();
		num=0;
		num_cur = 0;
		cur=tail=head=0;
	}
	else
	{
		num = size;
		for(int i = 0; i < num_cur-size;i++)
			del();
		
	}
}

void CircleQueue::show(int fid, bool reversFlag)
{
	if(fid < 0 || !head)
		return;
	if(!reversFlag)										
	{
		Node_Queue* work = head;
		do
		{
			write(fid, work->ptr, strlen(work->ptr));
			write(fid, "\n", 1);
			work = work->next;
		}while(work != tail);
		write(fid, work->ptr, strlen(work->ptr));
		write(fid, "\n", 1);
		write(fid, "\0", 1);
	}
	else						//show as revers order.tail first, head last.													
	{
		Node_Queue* work = tail;
		do
		{
			write(fid, work->ptr, strlen(work->ptr));
			write(fid, "\n", 1);
			work = work->pre;
		}while(work != head);
		write(fid, work->ptr, strlen(work->ptr));
		write(fid, "\n", 1);
		write(fid, "\0", 1);
	}
	return;
}