OpenRTMFP/Cumulus Primer(12)IO管理之IO流(续)
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OpenRTMFP/Cumulus Primer(12)IO管理之IO流(续)
- Author: 柳大·Poechant(钟超)
- Email: zhongchao.ustc#gmail.com (#->@)
- Blog: Blog.CSDN.net/Poechant
- Date: April 24th, 2012
0 导语
本文所介绍的 CumulusServer 中用到的 IO 流,是基于 CumulusServer 中的 MemoryIOS 的,可以先阅读《OpenRTMFP/Cumulus Primer(11)IO 管理之IO流》一文,然后再阅读本文。
1 输入流
class MemoryInputStream: public MemoryIOS, public std::istream
{
public:
MemoryInputStream(const char* pBuffer,Poco::UInt32 bufferSize);
/// Creates a MemoryInputStream for the given memory area,
/// ready for reading.
MemoryInputStream(MemoryInputStream&);
~MemoryInputStream();
/// Destroys the MemoryInputStream.
char* current();
};
构造函数、拷贝构造函数和析构函数也都没什么可说的,初始化 MemoryIOS 以及 istream。istream 是 iostream 中的 basic_istream 别名(typedef)。
MemoryInputStream::MemoryInputStream(const char* pBuffer, UInt32 bufferSize):
MemoryIOS(const_cast<char*>(pBuffer), bufferSize), istream(rdbuf()) {
}
MemoryInputStream::MemoryInputStream(MemoryInputStream& other):
MemoryIOS(other), istream(rdbuf()) {
}
MemoryInputStream::~MemoryInputStream() {
}
唯一的一个成员函数是 current,封装了 MemoryIOS 的 MemoryStreamBuf 成员的 gCurrent 函数:
inline char* MemoryInputStream::current() {
return rdbuf()->gCurrent();
}
2 输出流
class MemoryOutputStream: public MemoryIOS, public std::ostream
/// An input stream for reading from a memory area.
{
public:
MemoryOutputStream(char* pBuffer,Poco::UInt32 bufferSize);
/// Creates a MemoryOutputStream for the given memory area,
/// ready for writing.
MemoryOutputStream(MemoryOutputStream&);
~MemoryOutputStream();
/// Destroys the MemoryInputStream.
Poco::UInt32 written();
void written(Poco::UInt32 size);
char* current();
};
2.1 构造函数、拷贝构造函数和析构函数
如下,不赘述了。
MemoryOutputStream::MemoryOutputStream(char* pBuffer, UInt32 bufferSize):
MemoryIOS(pBuffer, bufferSize), ostream(rdbuf()) {
}
MemoryOutputStream::MemoryOutputStream(MemoryOutputStream& other):
MemoryIOS(other), ostream(rdbuf()) {
}
MemoryOutputStream::~MemoryOutputStream(){
}
2.2 读取和设定已写字节数
读取:
inline Poco::UInt32 MemoryOutputStream::written() {
return rdbuf()->written();
}
设定:
inline void MemoryOutputStream::written(Poco::UInt32 size) {
rdbuf()->written(size);
}
2.3 当前位置
与 MemoryInputStream 中的封装类似:
inline char* MemoryOutputStream::current() {
return rdbuf()->pCurrent();
}
-
转载请注明来自柳大的CSDN博客:Blog.CSDN.net/Poechant
-
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