blob.h

很好用的网络封装库,不熟悉网络编程的人也可以使用。使用风格良好的标准c++编写。

//
// BLOB.h
//
// $Id: //poco/1.3/Data/include/Poco/Data/BLOB.h#3 $
//
// Library: Data
// Package: DataCore
// Module:  BLOB
//
// Definition of the BLOB class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Data_BLOB_INCLUDED
#define Data_BLOB_INCLUDED


#include "Poco/Data/Data.h"
#include "Poco/SharedPtr.h"
#include "Poco/DynamicAnyHolder.h"
#include "Poco/Exception.h"
#include <vector>


namespace Poco {
namespace Data {


class Data_API BLOB
	/// Representation of a Binary Large OBject.
	///
	/// A BLOB can hold arbitrary binary data.
	/// The maximum size depends on the underlying database.
	///
	/// The BLOBInputStream and BLOBOutputStream classes provide
	/// a convenient way to access the data in a BLOB.
{
public:
	typedef std::vector<char>::const_iterator Iterator;

	BLOB();
		/// Creates an empty BLOB.

	BLOB(const std::vector<char>& content);
		/// Creates the BLOB, content is deep-copied.

	BLOB(const char* const pContent, std::size_t size);
		/// Creates the BLOB by deep-copying pContent.
		
	BLOB(const std::string& content);
		/// Creates a BLOB from a string.

	BLOB(const BLOB& other);
		/// Creates a BLOB by copying another one.

	~BLOB();
		/// Destroys the BLOB.

	BLOB& operator = (const BLOB& other);
		/// Assignment operator.

	bool operator == (const BLOB& other) const;
		/// Compares for equality BLOB by value.
		
	bool operator != (const BLOB& other) const;
		/// Compares for inequality BLOB by value.

	void swap(BLOB& other);
		/// Swaps the BLOB with another one.

	const std::vector<char>& content() const;
		/// Returns the content.

	const char* rawContent() const;
		/// Returns the raw content.

	void assignRaw(const char* pChar, std::size_t count);
		/// Assigns raw content to internal storage.

	void appendRaw(const char* pChar, std::size_t count);
		/// Assigns raw content to internal storage.

	void clear(bool doCompact = false);
		/// Clears the content of the blob.
		/// If doCompact is true, trims the excess capacity.

	void compact();
		/// Trims the internal storage excess capacity.

	Iterator begin() const;
	Iterator end() const;

	std::size_t size() const;
		/// Returns the size of the BLOB in bytes.

private:
	Poco::SharedPtr<std::vector<char> > _pContent;
	
	friend class BLOBStreamBuf;
};


//
// inlines
//
inline const std::vector<char>& BLOB::content() const
{
	return *_pContent;
}


inline const char* BLOB::rawContent() const
{
	return &(*_pContent)[0];
}


inline std::size_t BLOB::size() const
{
	return _pContent->size();
}


inline bool BLOB::operator == (const BLOB& other) const
{
	return *_pContent == *other._pContent;
}


inline bool BLOB::operator != (const BLOB& other) const
{
	return *_pContent != *other._pContent;
}


inline BLOB::Iterator BLOB::begin() const
{
	return _pContent->begin();
}


inline BLOB::Iterator BLOB::end() const
{
	return _pContent->end();
}


inline void BLOB::assignRaw(const char* pChar, std::size_t count)
{
	poco_assert_dbg (pChar);
	BLOB tmp(pChar, count);
	swap(tmp);
}


inline void BLOB::appendRaw(const char* pChar, std::size_t count)
{
	poco_assert_dbg (pChar);
	_pContent->insert(_pContent->end(), pChar, pChar+count);
}


inline void BLOB::swap(BLOB& other)
{
	using std::swap;
	swap(_pContent, other._pContent);
}


inline void BLOB::clear(bool doCompact)
{
	_pContent->clear();
	if (doCompact) compact();
}


inline void BLOB::compact()
{
	std::vector<char>(*_pContent).swap(*_pContent);
}


} } // namespace Poco::Data


//
// DynamicAnyHolderImpl<BLOB>
//


namespace Poco {


template <>
class DynamicAnyHolderImpl<Data::BLOB>: public DynamicAnyHolder
{
public:
	DynamicAnyHolderImpl(const Data::BLOB& val): _val(val)
	{
	}

	~DynamicAnyHolderImpl()
	{
	}
	
	const std::type_info& type() const
	{
		return typeid(Data::BLOB);
	}

	void convert(Int8& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(Int16& val) const
	{
		throw Poco::BadCastException();
	}
	
	void convert(Int32& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(Int64& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(UInt8& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(UInt16& val) const
	{
		throw Poco::BadCastException();
	}
	
	void convert(UInt32& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(UInt64& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(bool& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(float& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(double& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(char& val) const
	{
		throw Poco::BadCastException();
	}

	void convert(std::string& val) const
	{
		val.assign(_val.begin(), _val.end());
	}

	DynamicAnyHolder* clone() const
	{
		return new DynamicAnyHolderImpl(_val);
	}
	
private:
	Data::BLOB _val;
};


} // namespace Poco


#endif // Data_BLOB_INCLUDED