From:	Nigel Stephens <algor!nigel>
Date:	Sat, 6 Jun 92 21:45:24 BST
To:	djgpp AT sun DOT soe DOT clarkson DOT edu
Subject:	fix to libpc(gppconio)

I just found and fixed a couple of bugs in the window scrolling code
in the gppconio.c module in libpc.a.  There are a few other changes
which are not bug fixes, but which tidy up the code a little.

The diffs follow...
--------------------
Nigel Stephens
Algorithmics Ltd		UUCP:	nigel AT algor DOT co DOT uk
3 Drayton Park			OLDUUCP:..!mcsun!uknet!algor!nigel
London				PHONE:	(+44) 71 700 3301
N5 1NU				FAX:	(+44) 71 700 3400
England

*** gppconio.c	Sun Mar 29 21:21:46 1992
--- gppconio.c.new	Sat Jun  6 21:34:41 1992
***************
*** 11,16 ****
--- 11,17 ----
   *  when        who                 what
   *  -------------------------------------------------------------------
   *  10/27/91    J. Alan Eldridge    created
+  *   6/ 6/92	Nigel Stephens	    fixed scrolling and VIDADDR macro
   *
   *********************************************************************/
  
***************
*** 24,30 ****
  
  static struct text_info txinfo;
  
! #define VIDADDR(r,c) (ScreenPrimary + r * txinfo.screenwidth + c)
  
  int puttext(int c, int r, int c2, int r2, void *buf)
  {
--- 25,31 ----
  
  static struct text_info txinfo;
  
! #define VIDADDR(r,c) (ScreenPrimary + (r) * txinfo.screenwidth + (c))
  
  int puttext(int c, int r, int c2, int r2, void *buf)
  {
***************
*** 146,172 ****
          *VIDADDR(row, col) = fill;
  }
  
! static void scrollwin(int t, int b, int l)
  {
      int top = txinfo.wintop + t - 1, left = txinfo.winleft - 1,
!         bot = txinfo.wintop + b - 1, right = txinfo.winright - 1;
      
      int row, col, nbytes, fill, nlines;
      
!     if (!l) 
          return;
      
      nbytes = (right - left + 1) * 2;
-     nlines = (bot - top + 1) - l;
  
      fill = ' ' | (ScreenAttrib << 8);
  
      if (l > 0) {
!         for (row = top; nlines > 0; row++, nlines--)
              memcpy(VIDADDR(row, left), VIDADDR(row + l, left), nbytes);
          for (; row <= bot; row++)
              fillrow(row, left, right, fill);
      } else {
          for (row = bot; nlines > 0; row--, nlines--)
              memcpy(VIDADDR(row, left), VIDADDR(row + l, left), nbytes);
          for (; row >= top; row--)
--- 147,174 ----
          *VIDADDR(row, col) = fill;
  }
  
! static void scrollwin(int t, int l)
  {
      int top = txinfo.wintop + t - 1, left = txinfo.winleft - 1,
!         bot = txinfo.winbottom - 1, right = txinfo.winright - 1;
      
      int row, col, nbytes, fill, nlines;
      
!     if (l == 0) 
          return;
      
      nbytes = (right - left + 1) * 2;
  
      fill = ' ' | (ScreenAttrib << 8);
  
      if (l > 0) {
! 	nlines = (bot - top + 1) - l;
!         for (row = top; nlines > 0; row++, nlines--) 
              memcpy(VIDADDR(row, left), VIDADDR(row + l, left), nbytes);
          for (; row <= bot; row++)
              fillrow(row, left, right, fill);
      } else {
+ 	nlines = (bot - top + 1) + l;
          for (row = bot; nlines > 0; row--, nlines--)
              memcpy(VIDADDR(row, left), VIDADDR(row + l, left), nbytes);
          for (; row >= top; row--)
***************
*** 176,182 ****
  
  void clrscr(void)
  {
!     scrollwin(0, txinfo.winbottom - txinfo.wintop, 32000);
  }
  
  int putch(int c)
--- 178,184 ----
  
  void clrscr(void)
  {
!     scrollwin (0, 1000);
  }
  
  int putch(int c)
***************
*** 192,205 ****
      else if (c == '\r')
          col = txinfo.winleft - 1;
      else {
!         short   val = c | (ScreenAttrib << 8);
! 
!         puttext(col + 1, row + 1, col + 1, row + 1, &val);
          col++;
      }
      
      /* now, readjust the window     */
-     
      if (col >= txinfo.winright) {
          col = txinfo.winleft - 1;
          row++;
--- 194,204 ----
      else if (c == '\r')
          col = txinfo.winleft - 1;
      else {
! 	*VIDADDR(row,col) = c | (ScreenAttrib << 8);
          col++;
      }
      
      /* now, readjust the window     */
      if (col >= txinfo.winright) {
          col = txinfo.winleft - 1;
          row++;
***************
*** 206,212 ****
      }
      
      if (row >= txinfo.winbottom) {
!         scrollwin(0, txinfo.winbottom - txinfo.wintop, 1);
          row--;
      }
      
--- 205,211 ----
      }
      
      if (row >= txinfo.winbottom) {
!         scrollwin(0, 1);
          row--;
      }
      
***************
*** 226,237 ****
  
  void delline(void)
  {
!     scrollwin(wherey() - 1, txinfo.winbottom - txinfo.wintop, 1);
  }
  
  void insline(void)
  {
!     scrollwin(wherey() - 1, txinfo.winbottom - txinfo.wintop, -1);
  }
  
  void window(int left, int top, int right, int bottom)
--- 225,236 ----
  
  void delline(void)
  {
!     scrollwin(wherey() - 1, 1);
  }
  
  void insline(void)
  {
!     scrollwin(wherey() - 1, -1);
  }
  
  void window(int left, int top, int right, int bottom)

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