Replacement for the "Bar" function

[Warmaster199]

The Bar function draws a filled in rectangle. It comes with BorlandC and uses the BGI graphics device drivers. I have a replacement, but it only correctly works in mode 0x13, 320x200x256color. Here is my version of the bar function:

//These may be of use:
typedef unsigned char  byte;
typedef unsigned short word;

#define SCREEN_WIDTH        320       /* width in pixels of mode 0x13 */
#define SCREEN_HEIGHT       200       /* height in pixels of mode 0x13 */
#define NUM_COLORS          256       /* number of colors in mode 0x13 */
byte *xVGA=(byte *)0xA0000000L;

//The actual function
void rect_fill(int left,int top, int right, int bottom, byte color)
{
  word top_offset,bottom_offset,i,temp,width;

  if (top>bottom)
  {
    temp=top;
    top=bottom;
    bottom=temp;
  }
  if (left>right)
  {
    temp=left;
    left=right;
    right=temp;
  }

  top_offset=(top<<8)+(top<<6)+left;
  bottom_offset=(bottom<<8)+(bottom<<6)+left;
  width=right-left+1;

  for(i=top_offset;i<=bottom_offset;i+=SCREEN_WIDTH)
  {
    memset(&xVGA[i],color,width);
  }
} 

This function draws a filled rectangle using mode 0x13. If you change the above variable's values, as well as the video mode, it WILL NOT correctly work in the mode you have selected.

The problem I get with the function above is that it does NOT work correctly. It displays in incorrect places and it doesn't create a filled rectangle as big as it's supposed to be.

I need a replacement for this function that will work in ALL video modes. Work someone please help find a function like the above.