bitmap.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。

/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Bitmap decompression routines
   Copyright (C) Matthew Chapman 1999-2005

   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.
*/

/* three seperate function for speed when decompressing the bitmaps */
/* when modifing one function make the change in the others */
/* comment out #define BITMAP_SPEED_OVER_SIZE below for one slower function */
/* [e-mail] */

#define BITMAP_SPEED_OVER_SIZE

/* indent is confused by this file */
/* *INDENT-OFF* */

#include "rdesktop.h"

#define CVAL(p)   (*(p++))
#ifdef NEED_ALIGN
#ifdef L_ENDIAN
#define CVAL2(p, v) { v = (*(p++)); v |= (*(p++)) << 8; }
#else
#define CVAL2(p, v) { v = (*(p++)) << 8; v |= (*(p++)); }
#endif /* L_ENDIAN */
#else
#define CVAL2(p, v) { v = (*((uint16*)p)); p += 2; }
#endif /* NEED_ALIGN */

#define UNROLL8(exp) { exp exp exp exp exp exp exp exp }

#define REPEAT(statement) \
{ \
	while((count & ~0x7) && ((x+8) < width)) \
		UNROLL8( 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; \
	} \
}

#ifdef BITMAP_SPEED_OVER_SIZE

/* 1 byte bitmap decompress */
static BOOL
bitmap_decompress1(uint8 * output, int width, int height, uint8 * input, int size)
{
	uint8 *end = input + size;
	uint8 *prevline = NULL;
	int opcode, count, offset, isfillormix;
	int lastopcode = -1, insertmix = False, bicolour = False;
	uint8 code;
	uint8 colour1 = 0, colour2 = 0;
	uint8 mixmask, mask = 0;
	uint8 mix = 0xff;
	int fom_mask = 0;
#if 0
	uint8 *line = NULL;
	int x = width;
#else
	uint8 *line = output;
	int x = 0;
	int y = 0;
#endif

	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;
				if (opcode < 9)
				{
					count = CVAL(input);
					count |= CVAL(input) << 8;
				}
				else
				{
					count = (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;
				else
					count = CVAL(input) + offset;
			}
			else if (isfillormix)
			{
				count <<= 3;
			}
		}
		/* 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 0
				if (height <= 0)
#else
				if (y >= height)
#endif
					return False;
				x = 0;

#if 0
				height--;
#else
				y ++;
#endif

				prevline = line;

#if 0
				line = output + height * width;
#else
				line = output + y * width;
#endif
			}
			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 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] = 0)
					break;
				default:
					unimpl("bitmap opcode 0x%x\n", opcode);
					return False;
			}
		}
	}
	return True;
}

/* 2 byte bitmap decompress */
static BOOL
bitmap_decompress2(uint8 * output, int width, int height, uint8 * input, int size)
{
	uint8 *end = input + size;
	uint16 *prevline = NULL;
	int opcode, count, offset, isfillormix;
	int lastopcode = -1, insertmix = False, bicolour = False;
	uint8 code;
	uint16 colour1 = 0, colour2 = 0;
	uint8 mixmask, mask = 0;
	uint16 mix = 0xffff;
	int fom_mask = 0;
#if 0
	uint8 *line = NULL;
	int x = width;
#else
	uint8 *line = output;
	int x = 0;
	int y = 0;
#endif

	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;
				if (opcode < 9)
				{
					count = CVAL(input);
					count |= CVAL(input) << 8;
				}
				else
				{
					count = (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;
				else
					count = CVAL(input) + offset;
			}
			else if (isfillormix)
			{
				count <<= 3;
			}
		}
		/* Read preliminary data */
		switch (opcode)
		{
			case 0:	/* Fill */
				if ((lastopcode == opcode) && !((x == width) && (prevline == NULL)))
					insertmix = True;
				break;
			case 8:	/* Bicolour */
				CVAL2(input, colour1);
			case 3:	/* Colour */
				CVAL2(input, colour2);
				break;
			case 6:	/* SetMix/Mix */
			case 7:	/* SetMix/FillOrMix */
				CVAL2(input, mix);
				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 0
				if (height <= 0)
#else
				if (y >= height)
#endif
					return False;
				x = 0;

#if 0
				height--;
#else
				y ++;
#endif

				prevline = line;

#if 0
				line = ((uint16 *) output) + height * width;
#else
				line = ((uint16 *) output) + y * width;
#endif
			}
			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(CVAL2(input, line[x]))
					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] = 0xffff)
					break;
				case 0xe:	/* Black */
					REPEAT(line[x] = 0)
					break;
				default:
					unimpl("bitmap opcode 0x%x\n", opcode);
					return False;
			}
		}
	}
	return True;
}

/* 3 byte bitmap decompress */
static BOOL
bitmap_decompress3(uint8 * output, int width, int height, uint8 * input, int size)
{
	uint8 *end = input + size;
	uint8 *prevline = NULL;
	int opcode, count, offset, isfillormix;
	int lastopcode = -1, insertmix = False, bicolour = False;
	uint8 code;
	uint8 colour1[3] = {0, 0, 0}, colour2[3] = {0, 0, 0};
	uint8 mixmask, mask = 0;
	uint8 mix[3] = {0xff, 0xff, 0xff};
	int fom_mask = 0;
#if 0
	uint8 *line = NULL;
	int x = width;
#else
	uint8 *line = output;
	int x = 0;
	int y = 0;
#endif

	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;
				if (opcode < 9)
				{
					count = CVAL(input);
					count |= CVAL(input) << 8;
				}