slsmg.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/* SLang Screen management routines */
/* Copyright (c) 1992, 1995 John E. Davis
 * All rights reserved.
 *
 * You may distribute under the terms of either the GNU General Public
 * License or the Perl Artistic License.
 */

#include "config.h"

#include <stdio.h>
#include <string.h>

#include "slang.h"
#include "_slang.h"

typedef struct Screen_Type
  {
     int n;                    /* number of chars written last time */
     int flags;                /* line untouched, etc... */
     unsigned short *old, *neew;
#ifndef pc_system
     unsigned long old_hash, new_hash;
#endif
  }
Screen_Type;

#define TOUCHED 0x1
#define TRASHED 0x2

#ifndef pc_system
#define MAX_SCREEN_SIZE 120
#else
#define MAX_SCREEN_SIZE 75
#endif

Screen_Type SL_Screen[MAX_SCREEN_SIZE];
static int Start_Col, Start_Row;
static int Screen_Cols, Screen_Rows;
static int This_Row, This_Col;
static int This_Color;		       /* only the first 8 bits of this
					* are used.  The highest bit is used
					* to indicate an alternate character
					* set.  This leaves 127 userdefineable
					* color combination.
					*/

#ifndef pc_system
#define ALT_CHAR_FLAG 0x80
#else
#define ALT_CHAR_FLAG 0x00
#endif

int SLsmg_Newline_Moves = 0;
int SLsmg_Backspace_Moves = 0;

static void blank_line (unsigned short *p, int n, unsigned char ch)
{
   register unsigned short *pmax = p + n;
   register unsigned short color_ch;

   color_ch = (This_Color << 8) | (unsigned short) ch;

   while (p < pmax)
     {
	*p++ = color_ch;
     }
}


static void clear_region (int row, int n)
{
   int i;
   int imax = row + n;

   if (imax > Screen_Rows) imax = Screen_Rows;
   for (i = row; i < imax; i++)
     {
	if (i >= 0)
	  {
	     blank_line (SL_Screen[i].neew, Screen_Cols, ' ');
	     SL_Screen[i].flags |= TOUCHED;
	  }
     }
}

void SLsmg_erase_eol (void)
{
   int r, c;

   c = This_Col - Start_Col;
   r = This_Row - Start_Row;

   if ((r < 0) || (r >= Screen_Rows)) return;
   if (c < 0) c = 0; else if (c >= Screen_Cols) return;
   blank_line (SL_Screen[This_Row].neew + c , Screen_Cols - c, ' ');
   SL_Screen[This_Row].flags |= TOUCHED;
}

static void scroll_up (void)
{
   unsigned int i, imax;
   unsigned short *neew;

   neew = SL_Screen[0].neew;
   imax = Screen_Rows - 1;
   for (i = 0; i < imax; i++)
     {
	SL_Screen[i].neew = SL_Screen[i + 1].neew;
	SL_Screen[i].flags |= TOUCHED;
     }
   SL_Screen[i].neew = neew;
   SL_Screen[i].flags |= TOUCHED;
   blank_line (neew, Screen_Cols, ' ');
   This_Row--;
}




void SLsmg_gotorc (int r, int c)
{
   This_Row = r;
   This_Col = c;
}

int SLsmg_get_row (void)
{
   return This_Row;
}

int SLsmg_get_column (void)
{
   return This_Col;
}

void SLsmg_erase_eos (void)
{
   SLsmg_erase_eol ();
   clear_region (This_Row + 1, Screen_Rows);
}

static int This_Alt_Char;

#ifndef pc_system
void SLsmg_set_char_set (int i)
{
   if (SLtt_Use_Blink_For_ACS) return; /* alt chars not used and the alt bit
					* is used to indicate a blink.
					*/
   if (i) This_Alt_Char = ALT_CHAR_FLAG;
   else This_Alt_Char = 0;

   This_Color &= 0x7F;
   This_Color |= This_Alt_Char;
}
#endif

void SLsmg_set_color (int color)
{
   if (color < 0) return;
   This_Color = color | This_Alt_Char;
}


void SLsmg_reverse_video (void)
{
   SLsmg_set_color (1);
}


void SLsmg_normal_video (void)
{
   This_Color = This_Alt_Char;	       /* reset video but NOT char set. */
}


static int point_visible (int col_too)
{
   return ((This_Row >= Start_Row) && (This_Row < Start_Row + Screen_Rows)
	   && ((col_too == 0)
	       || ((This_Col >= Start_Col)
		   && (This_Col < Start_Col + Screen_Cols))));
}

void SLsmg_printf (char *fmt, ...)
{
   char p[1000];
   va_list ap;

   va_start(ap, fmt);
   (void) vsprintf(p, fmt, ap);
   va_end(ap);

   SLsmg_write_string (p);
}

void SLsmg_write_string (char *str)
{
   SLsmg_write_nchars (str, strlen (str));
}

void SLsmg_write_nstring (char *str, int n)
{
   int width;
   char blank = ' ';
   if (str == NULL) width = 0;
   else
     {
	width = strlen (str);
	if (width > n) width = n;
	SLsmg_write_nchars (str, width);
     }
   while (width++ < n) SLsmg_write_nchars (&blank, 1);
}

void SLsmg_write_wrapped_string (char *s, int r, int c, int dr, int dc, int fill)
{
   register char ch, *p;
   int maxc = dc;

   if ((dr == 0) || (dc == 0)) return;
   p = s;
   dc = 0;
   while (1)
     {
	ch = *p++;
	if ((ch == 0) || (ch == '\n'))
	  {
	     int diff;

	     diff = maxc - dc;

	     SLsmg_gotorc (r, c);
	     SLsmg_write_nchars (s, dc);
	     if (fill && (diff > 0))
	       {
		  while (diff--) SLsmg_write_char (' ');
	       }
	     if ((ch == 0) || (dr == 1)) break;

	     r++;
	     dc = 0;
	     dr--;
	     s = p;
	  }
	else if (dc == maxc)
	  {
	     SLsmg_gotorc (r, c);
	     SLsmg_write_nchars (s, dc + 1);
	     if (dr == 1) break;

	     r++;
	     dc = 0;
	     dr--;
	     s = p;
	  }
	else dc++;
     }
}



int SLsmg_Tab_Width = 8;

/* Minimum value for which eight bit char is displayed as is. */

#ifndef pc_system
int SLsmg_Display_Eight_Bit = 160;
static unsigned char Alt_Char_Set[129];/* 129th is used as a flag */
#else
int SLsmg_Display_Eight_Bit = 128;
#endif

void SLsmg_write_nchars (char *str, int n)
{
   register unsigned short *p, old, neew, color;
   unsigned char ch;
   unsigned int flags;
   int len, start_len, max_len;
   char *str_max;
   int newline_flag;
#ifndef pc_system
   int alt_char_set_flag;

   alt_char_set_flag = ((SLtt_Use_Blink_For_ACS == 0)
			&& (This_Color & ALT_CHAR_FLAG));
#endif

   str_max = str + n;
   color = This_Color << 8;

   top:				       /* get here only on newline */

   newline_flag = 0;
   start_len = Start_Col;

   if (point_visible (0) == 0) return;

   len = This_Col;
   max_len = start_len + Screen_Cols;

   p = SL_Screen[This_Row].neew;
   if (len > start_len) p += (len - start_len);

   flags = SL_Screen[This_Row].flags;
   while ((len < max_len) && (str < str_max))
     {
	ch = (unsigned char) *str++;

#ifndef pc_system
	if (alt_char_set_flag)
	  ch = Alt_Char_Set [ch & 0x7F];
#endif
	if (((ch >= ' ') && (ch < 127))
	    || (ch >= (unsigned char) SLsmg_Display_Eight_Bit)
#ifndef pc_system
	    || alt_char_set_flag
#endif
	    )
	  {
	     len += 1;
	     if (len > start_len)
	       {
		  old = *p;
		  neew = color | (unsigned short) ch;
		  if (old != neew)
		    {
		       flags |= TOUCHED;
		       *p = neew;
		    }
		  p++;
	       }
	  }

	else if ((ch == '\t') && (SLsmg_Tab_Width > 0))
	  {
	     n = len;
	     n += SLsmg_Tab_Width;
	     n = SLsmg_Tab_Width - (n % SLsmg_Tab_Width);
	     if (len + n > max_len) n = max_len - len;
	     neew = color | (unsigned short) ' ';
	     while (n--)
	       {
		  len += 1;
		  if (len > start_len)
		    {
		       if (*p != neew)
			 {
			    flags |= TOUCHED;
			    *p = neew;
			 }
		       p++;
		    }
	       }
	  }
	else if (ch == '\n')
	  {
	     newline_flag = 1;
	     break;
	  }
	else if ((ch == 0x8) && SLsmg_Backspace_Moves)
	  {
	     if (len != 0) len--;
	  }
	else
	  {
	     if (ch & 0x80)
	       {
		  neew = color | (unsigned short) '~';
		  len += 1;
		  if (len > start_len)
		    {
		       if (*p != neew)
			 {
			    *p = neew;
			    flags |= TOUCHED;
			 }
		       p++;
		       if (len == max_len) break;
		       ch &= 0x7F;
		    }
	       }

	     len += 1;
	     if (len > start_len)
	       {
		  neew = color | (unsigned short) '^';
		  if (*p != neew)
		    {
		       *p = neew;
		       flags |= TOUCHED;
		    }
		  p++;
		  if (len == max_len) break;
	       }

	     if (ch == 127) ch = '?'; else ch = ch + '@';
	     len++;
	     if (len > start_len)
	       {
		  neew = color | (unsigned short) ch;
		  if (*p != neew)
		    {
		       *p = neew;
		       flags |= TOUCHED;
		    }
		  p++;
	       }
	  }
     }

   SL_Screen[This_Row].flags = flags;
   This_Col = len;

   if (SLsmg_Newline_Moves == 0)
     return;

   if (newline_flag == 0)
     {
	while (str < str_max)
	  {
	     if (*str == '\n') break;
	     str++;
	  }
	if (str == str_max) return;
	str++;
     }

   This_Row++;
   This_Col = 0;
   if (This_Row == Start_Row + Screen_Rows)
     {
	if (SLsmg_Newline_Moves > 0) scroll_up ();
     }
   goto top;
}


void SLsmg_write_char (char ch)
{
   SLsmg_write_nchars (&ch, 1);
}

static int Cls_Flag;


void SLsmg_cls (void)
{
   This_Color = 0;
   clear_region (0, Screen_Rows);
   This_Color = This_Alt_Char;
   Cls_Flag = 1;
}
#if 0
static void do_copy (unsigned short *a, unsigned short *b)
{
   unsigned short *amax = a + Screen_Cols;

   while (a < amax) *a++ = *b++;
}
#endif

#ifndef pc_system
int SLsmg_Scroll_Hash_Border = 0;
static unsigned long compute_hash (unsigned short *s, int n)
{
   register unsigned long h = 0, g;
   register unsigned long sum = 0;
   register unsigned short *smax, ch;
   int is_blank = 2;

   s += SLsmg_Scroll_Hash_Border;
   smax = s + (n - SLsmg_Scroll_Hash_Border);
   while (s < smax)
     {
	ch = *s++;
	if (is_blank && ((ch & 0xFF) != 32)) is_blank--;

	sum += ch;

	h = sum + (h << 3);
	if ((g = h & 0xE0000000UL) != 0)
	  {
	     h = h ^ (g >> 24);
	     h = h ^ g;
	  }
     }
   if (is_blank) return 0;
   return h;
}

static unsigned long Blank_Hash;

static void try_scroll (void)
{
   int i, j, di, r1, r2, rmin, rmax;
   unsigned long hash;
   int color, did_scroll = 0;
   unsigned short *tmp;
   int ignore;

   /* find region limits. */

   for (rmax = Screen_Rows - 1; rmax > 0; rmax--)
     {
	if (SL_Screen[rmax].new_hash != SL_Screen[rmax].old_hash)
	  {
	     r1 = rmax - 1;
	     if ((r1 == 0)
		 || (SL_Screen[r1].new_hash != SL_Screen[r1].old_hash))
	       break;

	     rmax = r1;
	  }
     }

   for (rmin = 0; rmin < rmax; rmin++)
     {
	if (SL_Screen[rmin].new_hash != SL_Screen[rmin].old_hash)
	  {
	     r1 = rmin + 1;
	     if ((r1 == rmax)
		 || (SL_Screen[r1].new_hash != SL_Screen[r1].old_hash))
	       break;

	     rmin = r1;
	  }
     }


   for (i = rmax; i > rmin; i--)
     {
	hash = SL_Screen[i].new_hash;
	if (hash == Blank_Hash) continue;

	if ((hash == SL_Screen[i].old_hash)
	    || ((i + 1 < Screen_Rows) && (hash == SL_Screen[i + 1].old_hash))
	    || ((i - 1 > rmin) && (SL_Screen[i].old_hash == SL_Screen[i - 1].new_hash)))
	  continue;

	for (j = i - 1; j >= rmin; j--)
	  {
	     if (hash == SL_Screen[j].old_hash) break;
	  }
	if (j < rmin) continue;

	r2 = i;			       /* end scroll region */

	di = i - j;
	j--;
	ignore = 0;
	while ((j >= rmin) && (SL_Screen[j].old_hash == SL_Screen[j + di].new_hash))
	  {
	     if (SL_Screen[j].old_hash == Blank_Hash) ignore++;
	     j--;
	  }
	r1 = j + 1;

	/* If this scroll only scrolls this line into place, don't do it.
	 */
	if ((di > 1) && (r1 + di + ignore == r2)) continue;

	/* If there is anything in the scrolling region that is ok, abort the
	 * scroll.
	 */

	for (j = r1; j <= r2; j++)
	  {
	     if ((SL_Screen[j].old_hash != Blank_Hash)
		 && (SL_Screen[j].old_hash == SL_Screen[j].new_hash))
	       {
		  /* See if the scroll is happens to scroll this one into place. */
		  if ((j + di > r2) || (SL_Screen[j].old_hash != SL_Screen[j + di].new_hash))
		    break;
	       }
	  }
	if (j <= r2) continue;

	color = This_Color;  This_Color = 0;
	did_scroll = 1;
	SLtt_normal_video ();
	SLtt_set_scroll_region (r1, r2);
	SLtt_goto_rc (0, 0);
	SLtt_reverse_index (di);
	SLtt_reset_scroll_region ();
	/* Now we have a hole in the screen.  Make the virtual screen look
	 * like it.
	 */
	for (j = r1; j <= r2; j++) SL_Screen[j].flags = TOUCHED;

	while (di--)
	  {