- it技术
- 生产者、消费者问题的互斥锁解决方法
#include <QCoreApplication>
#include <QThread>
#include <QTime>
#include <QMutex>
#include <QDebug>
class Work : public QObject
{
protected:
enum {WORKMAXSIZE
= 1024};
char work
[WORKMAXSIZE
];
int freeSize
;
int tail
;
int head
;
QMutex mutex
;
public:
Work()
{
memset(work
, 0, WORKMAXSIZE
);
freeSize
= WORKMAXSIZE
;
tail
= head
= 0;
}
bool product(char ch
)
{
if(freeSize
> 0)
{
qDebug() << "work product current thread: " << QThread
::currentThread();
mutex
.lock();
work
[tail
] = ch
;
tail
= (tail
+ 1) % WORKMAXSIZE
;
freeSize
--;
mutex
.unlock();
return true;
}
return false;
}
bool custom(int &ch
)
{
if(freeSize
< WORKMAXSIZE
)
{
qDebug() << "work custom current thread: " << QThread
::currentThread();
mutex
.lock();
ch
= work
[head
];
head
= (head
+ 1) % WORKMAXSIZE
;
freeSize
++;
mutex
.unlock();
return true;
}
return false;
}
};
Work work
;
class Productor : public QThread
{
protected:
char randChar()
{
qsrand(QDateTime
::currentDateTime().time().msec());
QThread
::msleep(1);
int ch
= qrand() % 52;
return (ch
< 26) ? static_cast<char>(ch
+ 'A') : static_cast<char>(ch
- 26 + 'a');
}
public slots
:
void run()
{
while(1)
{
qDebug() << "productor current thread: " << QThread
::currentThread();
int ch
= randChar();
qDebug() << "Productor: ch = " << ch
;
qDebug() << "Productor: flag = " << work
.product(ch
);
}
}
};
class Customer : public QThread
{
public slots
:
void run()
{
while(1)
{
qDebug() << "customer current thread: " << QThread
::currentThread();
int ch
= -1;
qDebug() << "Customer: flag = " << work
.custom(ch
);
qDebug() << "Customer: ch = " << ch
;
}
}
};
int main(int argc
, char *argv
[])
{
QCoreApplication
a(argc
, argv
);
Productor product
;
Customer custom
;
product
.start();
custom
.start();
return a
.exec();
}
