appclasses.cpp

封装的http和文件存取的c++类例子

#include "appclasses.h"
#include "AEEStdLib.h"

//--------------------------------------------------------------------------
// Writer class constructor
//--------------------------------------------------------------------------
Writer::Writer(IShell* pIShell)
{
    int charHeight, pnAscent, pnDescent;

    ISHELL_CreateInstance(pIShell, AEECLSID_DISPLAY, (void **)&m_pIDisplay);

    // Determine the amount of available screen space
    ISHELL_GetDeviceInfo(pIShell,&m_di);

    // Determine the height of a line of text
    charHeight = IDISPLAY_GetFontMetrics (m_pIDisplay, AEE_FONT_NORMAL,
      &pnAscent, &pnDescent);

    // Number of available lines equals the available screen
    // space divided by the height of a line, minus 3 for the
    // lines we always print at the top and bottom of the screen
    m_cMaxLine = (m_di.cyScreen / charHeight) - 3;
    m_cLineNum = 1;
    IDISPLAY_EraseRgn(m_pIDisplay, 0, 0, m_di.cxScreen, m_di.cyScreen);
    // WriteLine("Writer Constructor");
}

//--------------------------------------------------------------------------
// Writer class desctuctor
//--------------------------------------------------------------------------
Writer::~Writer()
{
    // WriteLine("Writer Destructor");
    IDISPLAY_Release(m_pIDisplay);
}

/*===========================================================================

FUNCTION: Writer::WriteLine

DESCRIPTION
    This function displays lines of text on the screen, taking into account
	the number of text lines printed so far and the number of lines available
	for output.

    If all available lines are exhausted, this function returns without doing
	anything.

    If the last available line of the screen is reached, this function prints
	"..." to indicate that some lines may not have been printed due to lack
	of space.

    Otherwise, this function prints the line on the screen by calling DisplayOutput,
	and updates the count of lines printed based on how many lines DisplayOutput
	used to print the text.
 
    
PROTOTYPE:
   static void WriteLine(char *pszStr)

PARAMETERS:
   pszStr:    [in]: The character string to be displayed on the screen.

DEPENDENCIES
  Assumes the m_cLineNum gets initialized to the starting line for text display
  on the screen, and that m_cMaxLine contains the last available line for 
  output on the screen.

RETURN VALUE
  None.

SIDE EFFECTS
  None

===========================================================================*/
void Writer::WriteLine(const char *pszStr)
{
    char ellipsis[4];
    STRCPY(ellipsis, "...");
	// If all available lines used, return
	if (m_cLineNum > m_cMaxLine)
		return;

	// If we've reached last available line, print an
	// ellipsis indicator
	if (m_cLineNum == m_cMaxLine)
	{
		DisplayOutput(m_cLineNum++, ellipsis);
	    return;
	}

	// There are lines available for printing.  Print the string passed as
	// input and update the count of lines available
    m_cLineNum += DisplayOutput(m_cLineNum, pszStr);
    IDISPLAY_UpdateEx(m_pIDisplay, TRUE);
	return;

} // End of WriteLine


void Writer::WriteLine(int i)
{
	char ch[12];
	SPRINTF(ch, "%ld", i);
	WriteLine(ch);

} //
//--------------------------------------------------------------------------
// Writer class operator <<
//--------------------------------------------------------------------------


//--------------------------------------------------------------------------
// Writer class operator new
//--------------------------------------------------------------------------


/*===========================================================================

FUNCTION: Writer::DisplayOutput

DESCRIPTION
    This function displays an output string at a given line number on the
    screen. If the nline parameter is a negative value (-1) the string
    is displayed in the middle of the screen. If the "nline" value is larger
    than or equal to zero the "nline" value is multiplied by 15 and the 
    resulting value in pixels is set to the y-coordinate of the start of 
    the string display on the screen. If the string does not fit on one line
    the string wraps around to the next line (spaced rougly 10-15 pixels apart).
    By default 5 is used as the starting the x-coordinate of a displayed 
    string.

    How many characters that fit on one line is calculated for each line 
    that is wrapped around to the next line.

    Note: depending on the phone screen size and the fonts used for characters 
          the output might differ on different handsets (devices). Where some 
          handsets will have a smaller screen and large default fonts which will 
          cause partial overlapping of lines. This function does not try to address
          these issues (this is meant as a simple display function).
    
PROTOTYPE:
   int DisplayOutput(int nline, char *pszStr)

PARAMETERS:
   nline:     [in]: Contains the line number to start displaying the text. The line
        numbers are by default spaced 15 pixels apart along the y-axis.
   pszStr:    [in]: The character string to be displayed on the screen.

DEPENDENCIES
  None

RETURN VALUE
  Number of lines written to the screen.

SIDE EFFECTS
  None

===========================================================================*/
int Writer::DisplayOutput(int nline, const char *pszStr)
{
   AECHAR * szBuf;     // a buffer that supports 200 char string
   AECHAR * psz = NULL;
   int charHeight = 0;      // Stores the char height in pixels for given font
   int pnAscent = 0;        // Stores the ascent in number of pixels
   int pnDescent = 0;       // Stores the descent in number of pixels
   int pixelWidth;
   AEEFont font = AEE_FONT_NORMAL;
   int pnFits = 0, dy;
   int totalCh = 0;
   int numLinesPrinted = 0;

   // Make sure the pointers we'll be using are valid
   if (m_pIDisplay == NULL)
	   return 0;

   if ((szBuf = (AECHAR *) MALLOC(TEXT_BUFFER_SIZE)) == NULL)
	   return 0;

   // Get the font metrics info
   charHeight = IDISPLAY_GetFontMetrics (m_pIDisplay, AEE_FONT_NORMAL,
      &pnAscent, &pnDescent);

   // Convert to wide string (unicode)
   STR_TO_WSTR ((char *)pszStr, szBuf, TEXT_BUFFER_SIZE);

   // If nlines is zero then print this string starting around the middle of 
   // the screen. Or else multiply nlines by charheight to decide the y coordinate of
   // the start of the string.
   if (nline < 0) {
      dy = m_di.cyScreen*2/5;
   }
   else{
      dy = nline * charHeight + 5;
   }

   // psz keeps track of the point from which to write from the string buffer
   // in case the string does not fit one line and needs to wrap around in the
   // next line.
   psz = szBuf;
      
   // Need to calculate the lotal string length to decide if any wrapping
   // around is needed.
   totalCh = STRLEN ((char *)pszStr);

   // Keep displaying text string on multiple lines if the string can't be displayed
   // on one single line. Lines are spaced 15 pixels apart.
   while ((totalCh > 0) && (*psz != NULL))
   { 
      // Get information on how many characters will fit in a line.
      // Give the pointer to the buffer to be displayed, and the number of
      // pixels along the x axis you want to display the string in (max number)
      // pnFits will have the max number of chars that will fit in the maxWidth
      // number of pixels (given string can't fit in one line), or the number of 
      // chars in the string (if it does fit in one line). pnWidth gives the
      // number of pixels that will be used to display pnFits number of chars.
      pixelWidth = IDISPLAY_MeasureTextEx(m_pIDisplay,
                      font, 
                      (AECHAR *) psz,  // Start of the buffer to display,
                      -1,
                      m_di.cxScreen - 5, // maxWidth
                      &pnFits);         // Number of chars that will fit a line

      // If pnFits is zero there is something wrong in the input to above function. 
      // Normally this scenario should not occur. But, have the check anyway.
      if (pnFits == 0)
	  {
		 FREE(szBuf);
         return 0;
	  }

      IDISPLAY_DrawText(m_pIDisplay, AEE_FONT_NORMAL, psz, pnFits, 5 /*start dx*/, 
         dy, 0 /* use default rectangle coordinates */, 0);

      psz += pnFits;      // move pointer to the next segment to be displayed
      totalCh -= pnFits;  // reduce the total number of characters to still display
      dy += charHeight;   // Place next line charHeight pixels below the 
                          // previous line.
	  ++numLinesPrinted;

      IDISPLAY_Update(m_pIDisplay); //, TRUE);
      if (totalCh < pnFits)
         pnFits = totalCh;  // if total number is less than pnFits, adjust pnFits
   }

   FREE(szBuf);

   return numLinesPrinted;   
} // End of DisplayOutput