/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library 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

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

#include "SDL_video.h"

#include "SDL_blit.h"

#include "SDL_sysvideo.h"

#include "SDL_endian.h"

/* Functions to blit from 8-bit surfaces to other surfaces */

static void Blit1to1(SDL_BlitInfo *info)

{

#ifndef USE_DUFFS_LOOP

	int c;

#endif

	int width, height;

	Uint8 *src, *map, *dst;

	int srcskip, dstskip;

	/* Set up some basic variables */

	width = info->d_width;

	height = info->d_height;

	src = info->s_pixels;

	srcskip = info->s_skip;

	dst = info->d_pixels;

	dstskip = info->d_skip;

	map = info->table;

	while ( height-- ) {

#ifdef USE_DUFFS_LOOP

		DUFFS_LOOP(

			{

			  *dst = map[*src];

			}

			dst++;

			src++;

		, width);

#else

		for ( c=width; c; --c ) {

		        *dst = map[*src];

			dst++;

			src++;

		}

#endif

		src += srcskip;

		dst += dstskip;

	}

}

/* This is now endian dependent */

#if ( SDL_BYTEORDER == SDL_LIL_ENDIAN )

#define HI	1

#define LO	0

#else /* ( SDL_BYTEORDER == SDL_BIG_ENDIAN ) */

#define HI	0

#define LO	1

#endif

static void Blit1to2(SDL_BlitInfo *info)

{

#ifndef USE_DUFFS_LOOP

	int c;

#endif

	int width, height;

	Uint8 *src, *dst;

	Uint16 *map;

	int srcskip, dstskip;

	/* Set up some basic variables */

	width = info->d_width;

	height = info->d_height;

	src = info->s_pixels;

	srcskip = info->s_skip;

	dst = info->d_pixels;

	dstskip = info->d_skip;

	map = (Uint16 *)info->table;

#ifdef USE_DUFFS_LOOP

	while ( height-- ) {

		DUFFS_LOOP(

		{

			*(Uint16 *)dst = map[*src++];

			dst += 2;

		},

		width);

		src += srcskip;

		dst += dstskip;

	}

#else

	/* Memory align at 4-byte boundary, if necessary */

	if ( (long)dst & 0x03 ) {

		/* Don't do anything if width is 0 */

		if ( width == 0 ) {

			return;

		}

		--width;

		while ( height-- ) {

			/* Perform copy alignment */

			*(Uint16 *)dst = map[*src++];

			dst += 2;

			/* Copy in 4 pixel chunks */

			for ( c=width/4; c; --c ) {

				*(Uint32 *)dst =

					(map[src[HI]]<<16)|(map[src[LO]]);

				src += 2;

				dst += 4;

				*(Uint32 *)dst =

					(map[src[HI]]<<16)|(map[src[LO]]);

				src += 2;

				dst += 4;

			}

			/* Get any leftovers */

			switch (width & 3) {

				case 3:

					*(Uint16 *)dst = map[*src++];

					dst += 2;

				case 2:

					*(Uint32 *)dst =

					  (map[src[HI]]<<16)|(map[src[LO]]);

					src += 2;

					dst += 4;

					break;

				case 1:

					*(Uint16 *)dst = map[*src++];

					dst += 2;

					break;

			}

			src += srcskip;

			dst += dstskip;

		}

	} else { 

		while ( height-- ) {

			/* Copy in 4 pixel chunks */

			for ( c=width/4; c; --c ) {

				*(Uint32 *)dst =

					(map[src[HI]]<<16)|(map[src[LO]]);

				src += 2;

				dst += 4;

				*(Uint32 *)dst =

					(map[src[HI]]<<16)|(map[src[LO]]);

				src += 2;

				dst += 4;

			}

			/* Get any leftovers */

			switch (width & 3) {

				case 3:

					*(Uint16 *)dst = map[*src++];

					dst += 2;

				case 2:

					*(Uint32 *)dst =

					  (map[src[HI]]<<16)|(map[src[LO]]);

					src += 2;

					dst += 4;

					break;

				case 1:

					*(Uint16 *)dst = map[*src++];

					dst += 2;

					break;

			}

			src += srcskip;

			dst += dstskip;

		}

	}

#endif /* USE_DUFFS_LOOP */

}

static void Blit1to3(SDL_BlitInfo *info)

{

#ifndef USE_DUFFS_LOOP

	int c;

#endif

	int o;

	int width, height;

	Uint8 *src, *map, *dst;

	int srcskip, dstskip;

	/* Set up some basic variables */

	width = info->d_width;

	height = info->d_height;

	src = info->s_pixels;

	srcskip = info->s_skip;

	dst = info->d_pixels;

	dstskip = info->d_skip;

	map = info->table;

	while ( height-- ) {

#ifdef USE_DUFFS_LOOP

		DUFFS_LOOP(

			{

				o = *src * 4;

				dst[0] = map[o++];

				dst[1] = map[o++];

				dst[2] = map[o++];

			}

			src++;

			dst += 3;

		, width);

#else

		for ( c=width; c; --c ) {

			o = *src * 4;

			dst[0] = map[o++];

			dst[1] = map[o++];

			dst[2] = map[o++];

			src++;

			dst += 3;

		}

#endif /* USE_DUFFS_LOOP */

		src += srcskip;

		dst += dstskip;

	}

}

static void Blit1to4(SDL_BlitInfo *info)

{

#ifndef USE_DUFFS_LOOP

	int c;

#endif

	int width, height;

	Uint8 *src;

	Uint32 *map, *dst;

	int srcskip, dstskip;

	/* Set up some basic variables */

	width = info->d_width;

	height = info->d_height;

	src = info->s_pixels;

	srcskip = info->s_skip;

	dst = (Uint32 *)info->d_pixels;

	dstskip = info->d_skip/4;

	map = (Uint32 *)info->table;

	while ( height-- ) {

#ifdef USE_DUFFS_LOOP

		DUFFS_LOOP(

			*dst++ = map[*src++];

		, width);

#else

		for ( c=width/4; c; --c ) {

			*dst++ = map[*src++];

			*dst++ = map[*src++];

			*dst++ = map[*src++];

			*dst++ = map[*src++];

		}

		switch ( width & 3 ) {

			case 3:

				*dst++ = map[*src++];

			case 2:

				*dst++ = map[*src++];

			case 1:

				*dst++ = map[*src++];

		}

#endif /* USE_DUFFS_LOOP */

		src += srcskip;

		dst += dstskip;

	}

}

static void Blit1to1Key(SDL_BlitInfo *info)

{

	int width = info->d_width;

	int height = info->d_height;

	Uint8 *src = info->s_pixels;

	int srcskip = info->s_skip;

	Uint8 *dst = info->d_pixels;

	int dstskip = info->d_skip;

	Uint8 *palmap = info->table;

	Uint32 ckey = info->src->colorkey;

	if ( palmap ) {

		while ( height-- ) {

			DUFFS_LOOP(

			{

				if ( *src != ckey ) {

				  *dst = palmap[*src];

				}

				dst++;

				src++;

			},

			width);

			src += srcskip;

			dst += dstskip;

		}

	} else {

		while ( height-- ) {

			DUFFS_LOOP(

			{

				if ( *src != ckey ) {

				  *dst = *src;

				}

				dst++;

				src++;

			},

			width);

			src += srcskip;

			dst += dstskip;

		}

	}

}

static void Blit1to2Key(SDL_BlitInfo *info)

{

	int width = info->d_width;

	int height = info->d_height;

	Uint8 *src = info->s_pixels;

	int srcskip = info->s_skip;

	Uint16 *dstp = (Uint16 *)info->d_pixels;

	int dstskip = info->d_skip;

	Uint16 *palmap = (Uint16 *)info->table;

	Uint32 ckey = info->src->colorkey;

	/* Set up some basic variables */

	dstskip /= 2;

	while ( height-- ) {

		DUFFS_LOOP(

		{

			if ( *src != ckey ) {

				*dstp=palmap[*src];

			}

			src++;

			dstp++;

		},

		width);

		src += srcskip;

		dstp += dstskip;

	}

}

static void Blit1to3Key(SDL_BlitInfo *info)

{

	int width = info->d_width;

	int height = info->d_height;

	Uint8 *src = info->s_pixels;

	int srcskip = info->s_skip;

	Uint8 *dst = info->d_pixels;

	int dstskip = info->d_skip;

	Uint8 *palmap = info->table;

	Uint32 ckey = info->src->colorkey;

	int o;

	while ( height-- ) {

		DUFFS_LOOP(

		{

			if ( *src != ckey ) {

				o = *src * 4;

				dst[0] = palmap[o++];

				dst[1] = palmap[o++];

				dst[2] = palmap[o++];

			}

			src++;

			dst += 3;

		},

		width);

		src += srcskip;

		dst += dstskip;

	}

}

static void Blit1to4Key(SDL_BlitInfo *info)

{

	int width = info->d_width;

	int height = info->d_height;

	Uint8 *src = info->s_pixels;

	int srcskip = info->s_skip;

	Uint32 *dstp = (Uint32 *)info->d_pixels;

	int dstskip = info->d_skip;

	Uint32 *palmap = (Uint32 *)info->table;

	Uint32 ckey = info->src->colorkey;

	/* Set up some basic variables */

	dstskip /= 4;

	while ( height-- ) {

		DUFFS_LOOP(

		{

			if ( *src != ckey ) {

				*dstp = palmap[*src];

			}

			src++;

			dstp++;

		},

		width);

		src += srcskip;

		dstp += dstskip;

	}

}

static void Blit1toNAlpha(SDL_BlitInfo *info)

{

	int width = info->d_width;

	int height = info->d_height;

	Uint8 *src = info->s_pixels;

	int srcskip = info->s_skip;

	Uint8 *dst = info->d_pixels;

	int dstskip = info->d_skip;

	SDL_PixelFormat *dstfmt = info->dst;

	const SDL_Color *srcpal	= info->src->palette->colors;

	int dstbpp;

	const int A = info->src->alpha;

	/* Set up some basic variables */

	dstbpp = dstfmt->BytesPerPixel;

	while ( height-- ) {

	        int sR, sG, sB;

		int dR, dG, dB;

	    	DUFFS_LOOP4(

			{

			        Uint32 pixel;

				sR = srcpal[*src].r;

				sG = srcpal[*src].g;

				sB = srcpal[*src].b;

				DISEMBLE_RGB(dst, dstbpp, dstfmt,

					     pixel, dR, dG, dB);

				ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);

			  	ASSEMBLE_RGB(dst, dstbpp, dstfmt, dR, dG, dB);

				src++;

				dst += dstbpp;

			},

			width);

		src += srcskip;

		dst += dstskip;

	}

}

static void Blit1toNAlphaKey(SDL_BlitInfo *info)

{

	int width = info->d_width;

	int height = info->d_height;

	Uint8 *src = info->s_pixels;

	int srcskip = info->s_skip;

	Uint8 *dst = info->d_pixels;

	int dstskip = info->d_skip;

	SDL_PixelFormat *srcfmt = info->src;

	SDL_PixelFormat *dstfmt = info->dst;

	const SDL_Color *srcpal	= info->src->palette->colors;

	Uint32 ckey = srcfmt->colorkey;

	int dstbpp;

	const int A = srcfmt->alpha;

	/* Set up some basic variables */

	dstbpp = dstfmt->BytesPerPixel;

	while ( height-- ) {

	        int sR, sG, sB;

		int dR, dG, dB;

		DUFFS_LOOP(

		{

			if ( *src != ckey ) {

			        Uint32 pixel;

				sR = srcpal[*src].r;

				sG = srcpal[*src].g;

				sB = srcpal[*src].b;

				DISEMBLE_RGB(dst, dstbpp, dstfmt,

							pixel, dR, dG, dB);

				ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);

			  	ASSEMBLE_RGB(dst, dstbpp, dstfmt, dR, dG, dB);

			}

			src++;

			dst += dstbpp;

		},

		width);

		src += srcskip;

		dst += dstskip;

	}

}

static SDL_loblit one_blit[] = {

	NULL, Blit1to1, Blit1to2, Blit1to3, Blit1to4

};

static SDL_loblit one_blitkey[] = {

        NULL, Blit1to1Key, Blit1to2Key, Blit1to3Key, Blit1to4Key

};

SDL_loblit SDL_CalculateBlit1(SDL_Surface *surface, int blit_index)

{

	int which;

	SDL_PixelFormat *dstfmt;

	dstfmt = surface->map->dst->format;

	if ( dstfmt->BitsPerPixel < 8 ) {

		which = 0;

	} else {

		which = dstfmt->BytesPerPixel;

	}

	switch(blit_index) {

	case 0:			/* copy */

	    return one_blit[which];

	case 1:			/* colorkey */

	    return one_blitkey[which];

	case 2:			/* alpha */

	    /* Supporting 8bpp->8bpp alpha is doable but requires lots of

	       tables which consume space and takes time to precompute,

	       so is better left to the user */

	    return which >= 2 ? Blit1toNAlpha : NULL;

	case 3:			/* alpha + colorkey */

	    return which >= 2 ? Blit1toNAlphaKey : NULL;

	}

	return NULL;

}