/*
   rdesktop: A Remote Desktop Protocol client.
   Bitmap decompression routines
   Copyright (C) Matthew Chapman 1999-2000
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rdesktop.h"

#define CVAL(p)   (*(p++))
#define SVAL(p)   ((*((p++) + 1) << 8) | CVAL(p))


/* #define REPEAT(statement) { while ((count > 0) && (x < width)) { statement; count--; x++; } } */

/* unroll defines, used to make the loops a bit more readable... */
#define unroll8Expr(uexp) uexp uexp uexp uexp uexp uexp uexp uexp

#define REPEAT(statement) \
{ \
 while( (count & ~0x7) && ( (x+8) < width)){ \
   unroll8Expr( statement; count--; x++; ); \
 } \
 while((count >0) && (x < width)) { statement; count--; x++; } \
}

#define MASK_UPDATE() { mixmask <<= 1; if (mixmask == 0) { mask = fom_mask ? fom_mask : CVAL(input); mixmask = 1; } }

Bool
bitmap_decompress (unsigned char *output, int width, int height,
		   unsigned char *input, int size)
{
  unsigned char *end = input + size;
  unsigned char *prevline = NULL, *line = NULL;
  int opcode, count, offset, isfillormix, x = width;
  int lastopcode = -1, insertmix = False, bicolour = False;
  uint8 code, colour1 = 0, colour2 = 0, packed_color1 = 0, packed_color2 = 0;
  uint8 mixmask, mask = 0, mix = 0xff;
  int fom_mask = 0;

  while (input < end)
    {
      fom_mask = 0;
      code = CVAL (input);
      opcode = code >> 4;

      /* Handle different opcode forms */
      switch (opcode)
	{

	case 0xc:
	case 0xd:
	case 0xe:
	  opcode -= 6;
	  count = code & 0xf;
	  offset = 16;
	  break;

	case 0xf:
	  opcode = code & 0xf;
	  count = (opcode < 9) ? SVAL (input) : (opcode < 0xb) ? 8 : 1;
	  offset = 0;
	  break;
	default:
	  opcode >>= 1;
	  count = code & 0x1f;
	  offset = 32;
	  break;
	}


      /* Handle strange cases for counts */
      if (offset != 0)
	{
	  isfillormix = ((opcode == 2) || (opcode == 7));

	  if (count == 0)
	    {
	      if (isfillormix)
		count = CVAL (input) + 1;	/* + 1 A8 / B8 -- 8b */
	      else
		count = CVAL (input) + offset;	/* +16 / +32 */
	    }
	  else if (isfillormix)
	    {
	      count <<= 3;	/* * 8 */
	    }
	}

      /* Read preliminary data */
      switch (opcode)
	{
	case 0:		/* Fill */
	  if ((lastopcode == opcode) && !((x >= width) && (prevline == NULL)))
	    insertmix = True;
	  break;
	case 8:		/* Bicolour */
	  colour1 = CVAL (input);
	case 3:		/* Colour */
	  colour2 = CVAL (input);
	  break;
	case 6:		/* SetMix/Mix */
	case 7:		/* SetMix/FillOrMix */
	  mix = CVAL (input);
	  opcode -= 5;
	  break;
	case 9:		/* FillOrMix_1 */
	  mask = 0x03;
	  opcode = 0x02;
	  fom_mask = 3;
	  break;
	case 0x0a:		/* FillOrMix_2 */
	  mask = 0x05;
	  opcode = 0x02;
	  fom_mask = 5;
	  break;

	}

      lastopcode = opcode;
      mixmask = 0;

      /* Output body */
      while (count > 0)
	{

	  if (x >= width)
	    {
	      if (height <= 0)
		return False;

	      x -= width;
	      height--;

	      prevline = line;
	      line = output + height * width;
	    }

	  switch (opcode)
	    {
	    case 0:		/* Fill */
	      if (insertmix)
		{
		  if (prevline == NULL)
		    line[x] = mix;
		  else
		    line[x] = prevline[x] ^ mix;

		  insertmix = False;
		  count--;
		  x++;
		}

	      if (prevline == NULL)
		REPEAT (line[x] = 0)
		else
		REPEAT (line[x] = prevline[x]) break;

	    case 1:		/* Mix */
	      if (prevline == NULL)
		REPEAT (line[x] = mix)
		else
		REPEAT (line[x] = prevline[x] ^ mix) break;

	    case 2:		/* Fill or Mix */
	      if (prevline == NULL)
		REPEAT (MASK_UPDATE (); if (mask & mixmask) line[x] = mix;
			else
			line[x] = 0;)
		else
		REPEAT (MASK_UPDATE ();
			if (mask & mixmask) line[x] = prevline[x] ^ mix;
			else
			line[x] = prevline[x];)
		break;

	    case 3:		/* Colour */
	      REPEAT (line[x] = colour2) break;
	    case 4:		/* Copy */
	      REPEAT (line[x] = CVAL (input)) break;
	    case 5:		/* CopyPacked DEBUG PLEASE */
	      REPEAT (packed_color1 = CVAL (input);
		      packed_color2 = packed_color1 & (uint8) 0x0f;
		      packed_color1 = packed_color1 & (uint8) 0xf0;
		      packed_color1 = packed_color1 >> 4;
		      line[x * 2] = packed_color1;
		      line[x * 2 + 1] = packed_color2;) break;
	    case 8:		/* Bicolour */
	      REPEAT (if (bicolour)
		      {
		      line[x] = colour2; bicolour = False;}
		      else
		      {
		      line[x] = colour1; bicolour = True; count++;}
	      )
		break;

	    case 0xd:		/* White */
	      REPEAT (line[x] = 0xff) break;

	    case 0xe:		/* Black */
	      REPEAT (line[x] = 0x00) break;

	    default:
	      NOTIMP ("bitmap opcode 0x%x (code: %x)\n", opcode, code);
	      return False;
	    }
	}
    }

  return True;
}