boundedbuffer.cc

来自「linux的例子,就是下载后到自己的机子上去运行」· CC 代码 · 共 125 行

#include "BoundedBuffer.h"

BoundedBuffer::BoundedBuffer(int maxsize)
{
	MaxSize = maxsize;
	buffer = new char[MaxSize];
	lock = new Lock("list lock");
	notEmpty = new Condition("list empty cond");
	notFull = new Condition("list full cond");
	n = in = out = 0;
}

BoundedBuffer::~BoundedBuffer()
{
	delete lock;
	delete notEmpty;
	delete notFull;
}

int BoundedBuffer::Read(void *data,int size)
{
	int lest,i,s,all = size,Rsize = 0;
	char *temp = new char[MaxSize];
	lock->Acquire();
	while(Rsize < all)
	{
		i = 0;
		while(n == 0)
			notEmpty->Wait(lock);
		lest = MaxSize - out;
		if(n > size)
		{
			if(lest >= size)
				memcpy(temp+Rsize,buffer+out,size);
			else
			{
				memcpy(temp+Rsize,buffer+out,lest);
				memcpy(temp+Rsize+lest,buffer,size - lest);
			}
			while(i<size)
			{
				buffer[out] = ' ';
				out = (out + 1)%MaxSize;
				i++;
			}
			n = n - size;
			Rsize = Rsize + size;
		}
		else
		{
			s = n;	
			if(lest >= s)
				memcpy(temp+Rsize,buffer+out,s);
			else
			{
				memcpy(temp+Rsize,buffer+out,lest);
				memcpy(temp+Rsize+lest,buffer,s-lest);
			}
			while(i<s)
			{
				buffer[out] = ' ' ;
				out = (out + 1)%MaxSize;
				i++;
			}
			n = 0;
			Rsize = Rsize + s;
			size = size - Rsize;
		}
	}
	memcpy(data,temp,all);
	notFull->Signal(lock);
	lock->Release();
	return 1;
}

int BoundedBuffer::Write(void *data,int size)
{
	int lest,s,all = size,Wsize = 0;
	char *temp = new char[MaxSize];
	memcpy(temp,data,size);
	lock->Acquire();
	while(Wsize < all)
	{
		while(n >= MaxSize)
			notFull->Wait(lock);
		lest = MaxSize - in;
		if(MaxSize-n > size)
		{
			if(lest >= size)
				memcpy(buffer+in,temp+Wsize,size);
			else
			{
				memcpy(buffer+in,temp+Wsize,lest);
				memcpy(buffer,temp+Wsize+lest,size-lest);
			}
			Wsize = Wsize + size;
			n = n + size;
			in = (in + size)%MaxSize;
		}
		else
		{
			s = MaxSize - n;
			if(lest >= s)
				memcpy(buffer+in,temp+Wsize,s);
			else
			{
				memcpy(buffer+in,temp+Wsize,lest);
				memcpy(buffer,temp+Wsize+lest,s-lest);
			}
			n = MaxSize;
			size = size - s;
			Wsize = Wsize + s;
			in = (in + s)%MaxSize;
		}
	}
	notEmpty->Signal(lock);
	lock->Release();
	return 1;
}

void BoundedBuffer::printbuffer()
{
	printf("buffer = %s\n",buffer);
}