TnbHttpFile.h

[詳解]

#pragma once
#include "TnbInternetHandle.h"
#include "TnbReader.h"
 
 
 
//TNB Library
namespace TNB
{
 
 
 
class CHttpFileReader : public IReader
{
    CInternetHandle m_hWininet; 
    CInternetHandle m_hFile;    
    CStr            m_strName;  
 
public:
    
    virtual LPCTSTR GetOpenName(void) const
    {
        return m_strName;
    }
 
    bool Open(LPCTSTR lpszAgent, LPCTSTR lpszUrl, DWORD_PTR dwContext = 0)
    {
        Close();
        if ( ! m_hWininet.Open(lpszAgent, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0) )
        {
            return false;
        }
        const DWORD dwFlags = INTERNET_FLAG_EXISTING_CONNECT | INTERNET_FLAG_RELOAD;
        m_hFile = m_hWininet.OpenUrl(lpszUrl, NULL, 0, dwFlags, dwContext);
        m_strName = lpszUrl;
        return m_hFile.IsValid();
    }
 
    virtual bool CanRead(void) const
    {
        return m_hFile.IsValid();
    }
 
    virtual size_t Read(size_t size, LPVOID _P) const
    {
        DWORD dwRead;
        if ( m_hFile.ReadFile(_P, size, &dwRead) )
        {
            return dwRead;
        }
        throw CReadFailureException(::GetLastError());
    }
 
    virtual LONGLONG Seek(LONGLONG llOffset, ESeekMode eSeek = TOP) const
    {
        LARGE_INTEGER r;
        r.QuadPart = llOffset;
        if ( r.HighPart == 0 )
        {
            r.LowPart = m_hFile.SetFilePointer(r.LowPart, 0, eSeek, 0);
            if ( r.LowPart == INVALID_SET_FILE_POINTER )
            {
                r.QuadPart = -1;
            }
        }
        else
        {
            r.QuadPart = -1;
        }
        return r.QuadPart;
    }
 
    virtual LONGLONG GetSize(void) const
    {
        LONGLONG l = Seek(0, CURRENT);
        LONGLONG r = Seek(0, END);
        if ( l >= 0 )
        {
            Seek(l, TOP);
        }
        return r;
    }
 
    void Close(void)
    {
        m_hFile.Close();
        m_hWininet.Close();
    }
 
    CInternetHandle& GetHandle(void)
    {
        return m_hFile;
    }
};
 
 
 
}; // TNB