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      1 /*
      2     SDL - Simple DirectMedia Layer
      3     Copyright (C) 1997-2012 Sam Lantinga
      4 
      5     This library is free software; you can redistribute it and/or
      6     modify it under the terms of the GNU Lesser General Public
      7     License as published by the Free Software Foundation; either
      8     version 2.1 of the License, or (at your option) any later version.
      9 
     10     This library is distributed in the hope that it will be useful,
     11     but WITHOUT ANY WARRANTY; without even the implied warranty of
     12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13     Lesser General Public License for more details.
     14 
     15     You should have received a copy of the GNU Lesser General Public
     16     License along with this library; if not, write to the Free Software
     17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
     18 
     19     Sam Lantinga
     20     slouken (at) libsdl.org
     21 */
     22 #include "SDL_config.h"
     23 
     24 /*
     25  * RLE encoding for software colorkey and alpha-channel acceleration
     26  *
     27  * Original version by Sam Lantinga
     28  *
     29  * Mattias Engdegrd (Yorick): Rewrite. New encoding format, encoder and
     30  * decoder. Added per-surface alpha blitter. Added per-pixel alpha
     31  * format, encoder and blitter.
     32  *
     33  * Many thanks to Xark and johns for hints, benchmarks and useful comments
     34  * leading to this code.
     35  *
     36  * Welcome to Macro Mayhem.
     37  */
     38 
     39 /*
     40  * The encoding translates the image data to a stream of segments of the form
     41  *
     42  * <skip> <run> <data>
     43  *
     44  * where <skip> is the number of transparent pixels to skip,
     45  *       <run>  is the number of opaque pixels to blit,
     46  * and   <data> are the pixels themselves.
     47  *
     48  * This basic structure is used both for colorkeyed surfaces, used for simple
     49  * binary transparency and for per-surface alpha blending, and for surfaces
     50  * with per-pixel alpha. The details differ, however:
     51  *
     52  * Encoding of colorkeyed surfaces:
     53  *
     54  *   Encoded pixels always have the same format as the target surface.
     55  *   <skip> and <run> are unsigned 8 bit integers, except for 32 bit depth
     56  *   where they are 16 bit. This makes the pixel data aligned at all times.
     57  *   Segments never wrap around from one scan line to the next.
     58  *
     59  *   The end of the sequence is marked by a zero <skip>,<run> pair at the *
     60  *   beginning of a line.
     61  *
     62  * Encoding of surfaces with per-pixel alpha:
     63  *
     64  *   The sequence begins with a struct RLEDestFormat describing the target
     65  *   pixel format, to provide reliable un-encoding.
     66  *
     67  *   Each scan line is encoded twice: First all completely opaque pixels,
     68  *   encoded in the target format as described above, and then all
     69  *   partially transparent (translucent) pixels (where 1 <= alpha <= 254),
     70  *   in the following 32-bit format:
     71  *
     72  *   For 32-bit targets, each pixel has the target RGB format but with
     73  *   the alpha value occupying the highest 8 bits. The <skip> and <run>
     74  *   counts are 16 bit.
     75  *
     76  *   For 16-bit targets, each pixel has the target RGB format, but with
     77  *   the middle component (usually green) shifted 16 steps to the left,
     78  *   and the hole filled with the 5 most significant bits of the alpha value.
     79  *   i.e. if the target has the format         rrrrrggggggbbbbb,
     80  *   the encoded pixel will be 00000gggggg00000rrrrr0aaaaabbbbb.
     81  *   The <skip> and <run> counts are 8 bit for the opaque lines, 16 bit
     82  *   for the translucent lines. Two padding bytes may be inserted
     83  *   before each translucent line to keep them 32-bit aligned.
     84  *
     85  *   The end of the sequence is marked by a zero <skip>,<run> pair at the
     86  *   beginning of an opaque line.
     87  */
     88 
     89 #include "SDL_video.h"
     90 #include "SDL_sysvideo.h"
     91 #include "SDL_blit.h"
     92 #include "SDL_RLEaccel_c.h"
     93 
     94 /* Force MMX to 0; this blows up on almost every major compiler now. --ryan. */
     95 #if 0 && defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) && SDL_ASSEMBLY_ROUTINES
     96 #define MMX_ASMBLIT
     97 #endif
     98 
     99 #ifdef MMX_ASMBLIT
    100 #include "mmx.h"
    101 #include "SDL_cpuinfo.h"
    102 #endif
    103 
    104 #ifndef MAX
    105 #define MAX(a, b) ((a) > (b) ? (a) : (b))
    106 #endif
    107 #ifndef MIN
    108 #define MIN(a, b) ((a) < (b) ? (a) : (b))
    109 #endif
    110 
    111 #define PIXEL_COPY(to, from, len, bpp)			\
    112 do {							\
    113     if(bpp == 4) {					\
    114 	SDL_memcpy4(to, from, (size_t)(len));		\
    115     } else {						\
    116 	SDL_memcpy(to, from, (size_t)(len) * (bpp));	\
    117     }							\
    118 } while(0)
    119 
    120 /*
    121  * Various colorkey blit methods, for opaque and per-surface alpha
    122  */
    123 
    124 #define OPAQUE_BLIT(to, from, length, bpp, alpha)	\
    125     PIXEL_COPY(to, from, length, bpp)
    126 
    127 #ifdef MMX_ASMBLIT
    128 
    129 #define ALPHA_BLIT32_888MMX(to, from, length, bpp, alpha)	\
    130     do {							\
    131 	Uint32 *srcp = (Uint32 *)(from);			\
    132 	Uint32 *dstp = (Uint32 *)(to);				\
    133         int i = 0x00FF00FF;					\
    134         movd_m2r(*(&i), mm3);					\
    135         punpckldq_r2r(mm3, mm3);				\
    136         i = 0xFF000000;						\
    137         movd_m2r(*(&i), mm7);					\
    138         punpckldq_r2r(mm7, mm7);				\
    139         i = alpha | alpha << 16;				\
    140         movd_m2r(*(&i), mm4);					\
    141         punpckldq_r2r(mm4, mm4);				\
    142 	pcmpeqd_r2r(mm5,mm5); /* set mm5 to "1" */		\
    143 	pxor_r2r(mm7, mm5); /* make clear alpha mask */		\
    144         i = length;						\
    145 	if(i & 1) {						\
    146           movd_m2r((*srcp), mm1); /* src -> mm1 */		\
    147           punpcklbw_r2r(mm1, mm1);				\
    148           pand_r2r(mm3, mm1);					\
    149 	  movd_m2r((*dstp), mm2); /* dst -> mm2 */		\
    150           punpcklbw_r2r(mm2, mm2);				\
    151           pand_r2r(mm3, mm2);					\
    152 	  psubw_r2r(mm2, mm1);					\
    153 	  pmullw_r2r(mm4, mm1);					\
    154 	  psrlw_i2r(8, mm1);					\
    155 	  paddw_r2r(mm1, mm2);					\
    156 	  pand_r2r(mm3, mm2);					\
    157 	  packuswb_r2r(mm2, mm2);				\
    158 	  pand_r2r(mm5, mm2); /* 00000RGB -> mm2 */		\
    159 	  movd_r2m(mm2, *dstp);					\
    160 	  ++srcp;						\
    161 	  ++dstp;						\
    162 	  i--;							\
    163 	}							\
    164 	for(; i > 0; --i) {					\
    165           movq_m2r((*srcp), mm0);				\
    166 	  movq_r2r(mm0, mm1);					\
    167           punpcklbw_r2r(mm0, mm0);				\
    168 	  movq_m2r((*dstp), mm2);				\
    169 	  punpckhbw_r2r(mm1, mm1);				\
    170 	  movq_r2r(mm2, mm6);					\
    171           pand_r2r(mm3, mm0);					\
    172           punpcklbw_r2r(mm2, mm2);				\
    173 	  pand_r2r(mm3, mm1);					\
    174 	  punpckhbw_r2r(mm6, mm6);				\
    175           pand_r2r(mm3, mm2);					\
    176 	  psubw_r2r(mm2, mm0);					\
    177 	  pmullw_r2r(mm4, mm0);					\
    178 	  pand_r2r(mm3, mm6);					\
    179 	  psubw_r2r(mm6, mm1);					\
    180 	  pmullw_r2r(mm4, mm1);					\
    181 	  psrlw_i2r(8, mm0);					\
    182 	  paddw_r2r(mm0, mm2);					\
    183 	  psrlw_i2r(8, mm1);					\
    184 	  paddw_r2r(mm1, mm6);					\
    185 	  pand_r2r(mm3, mm2);					\
    186 	  pand_r2r(mm3, mm6);					\
    187 	  packuswb_r2r(mm2, mm2);				\
    188 	  packuswb_r2r(mm6, mm6);				\
    189 	  psrlq_i2r(32, mm2);					\
    190 	  psllq_i2r(32, mm6);					\
    191 	  por_r2r(mm6, mm2);					\
    192 	  pand_r2r(mm5, mm2); /* 00000RGB -> mm2 */		\
    193          movq_r2m(mm2, *dstp);					\
    194 	  srcp += 2;						\
    195 	  dstp += 2;						\
    196 	  i--;							\
    197 	}							\
    198 	emms();							\
    199     } while(0)
    200 
    201 #define ALPHA_BLIT16_565MMX(to, from, length, bpp, alpha)	\
    202     do {						\
    203         int i, n = 0;					\
    204 	Uint16 *srcp = (Uint16 *)(from);		\
    205 	Uint16 *dstp = (Uint16 *)(to);			\
    206         Uint32 ALPHA = 0xF800;				\
    207 	movd_m2r(*(&ALPHA), mm1);			\
    208         punpcklwd_r2r(mm1, mm1);			\
    209         punpcklwd_r2r(mm1, mm1);			\
    210 	ALPHA = 0x07E0;					\
    211 	movd_m2r(*(&ALPHA), mm4);			\
    212         punpcklwd_r2r(mm4, mm4);			\
    213         punpcklwd_r2r(mm4, mm4);			\
    214 	ALPHA = 0x001F;					\
    215 	movd_m2r(*(&ALPHA), mm7);			\
    216         punpcklwd_r2r(mm7, mm7);			\
    217         punpcklwd_r2r(mm7, mm7);			\
    218 	alpha &= ~(1+2+4);				\
    219         i = (Uint32)alpha | (Uint32)alpha << 16;	\
    220         movd_m2r(*(&i), mm0);				\
    221         punpckldq_r2r(mm0, mm0);			\
    222         ALPHA = alpha >> 3;				\
    223         i = ((int)(length) & 3);			\
    224 	for(; i > 0; --i) {				\
    225 	    Uint32 s = *srcp++;				\
    226 	    Uint32 d = *dstp;				\
    227 	    s = (s | s << 16) & 0x07e0f81f;		\
    228 	    d = (d | d << 16) & 0x07e0f81f;		\
    229 	    d += (s - d) * ALPHA >> 5;			\
    230 	    d &= 0x07e0f81f;				\
    231 	    *dstp++ = d | d >> 16;			\
    232 	    n++;					\
    233 	}						\
    234 	i = (int)(length) - n;				\
    235 	for(; i > 0; --i) {				\
    236 	  movq_m2r((*dstp), mm3);			\
    237 	  movq_m2r((*srcp), mm2);			\
    238 	  movq_r2r(mm2, mm5);				\
    239 	  pand_r2r(mm1 , mm5);				\
    240 	  psrlq_i2r(11, mm5);				\
    241 	  movq_r2r(mm3, mm6);				\
    242 	  pand_r2r(mm1 , mm6);				\
    243 	  psrlq_i2r(11, mm6);				\
    244 	  psubw_r2r(mm6, mm5);				\
    245 	  pmullw_r2r(mm0, mm5);				\
    246 	  psrlw_i2r(8, mm5);				\
    247 	  paddw_r2r(mm5, mm6);				\
    248 	  psllq_i2r(11, mm6);				\
    249 	  pand_r2r(mm1, mm6);				\
    250 	  movq_r2r(mm4, mm5);				\
    251 	  por_r2r(mm7, mm5);				\
    252 	  pand_r2r(mm5, mm3);				\
    253 	  por_r2r(mm6, mm3);				\
    254 	  movq_r2r(mm2, mm5);				\
    255 	  pand_r2r(mm4 , mm5);				\
    256 	  psrlq_i2r(5, mm5);				\
    257 	  movq_r2r(mm3, mm6);				\
    258 	  pand_r2r(mm4 , mm6);				\
    259 	  psrlq_i2r(5, mm6);				\
    260 	  psubw_r2r(mm6, mm5);				\
    261 	  pmullw_r2r(mm0, mm5);				\
    262 	  psrlw_i2r(8, mm5);				\
    263 	  paddw_r2r(mm5, mm6);				\
    264 	  psllq_i2r(5, mm6);				\
    265 	  pand_r2r(mm4, mm6);				\
    266 	  movq_r2r(mm1, mm5);				\
    267 	  por_r2r(mm7, mm5);				\
    268 	  pand_r2r(mm5, mm3);				\
    269 	  por_r2r(mm6, mm3);				\
    270 	  movq_r2r(mm2, mm5);				\
    271 	  pand_r2r(mm7 , mm5);				\
    272           movq_r2r(mm3, mm6);				\
    273 	  pand_r2r(mm7 , mm6);				\
    274 	  psubw_r2r(mm6, mm5);				\
    275 	  pmullw_r2r(mm0, mm5);				\
    276 	  psrlw_i2r(8, mm5);				\
    277 	  paddw_r2r(mm5, mm6);				\
    278 	  pand_r2r(mm7, mm6);				\
    279 	  movq_r2r(mm1, mm5);				\
    280 	  por_r2r(mm4, mm5);				\
    281 	  pand_r2r(mm5, mm3);				\
    282 	  por_r2r(mm6, mm3);				\
    283 	  movq_r2m(mm3, *dstp);				\
    284 	  srcp += 4;					\
    285 	  dstp += 4;					\
    286 	  i -= 3;					\
    287 	}						\
    288 	emms();						\
    289     } while(0)
    290 
    291 #define ALPHA_BLIT16_555MMX(to, from, length, bpp, alpha)	\
    292     do {						\
    293         int i, n = 0;					\
    294 	Uint16 *srcp = (Uint16 *)(from);		\
    295 	Uint16 *dstp = (Uint16 *)(to);			\
    296         Uint32 ALPHA = 0x7C00;				\
    297 	movd_m2r(*(&ALPHA), mm1);			\
    298         punpcklwd_r2r(mm1, mm1);			\
    299         punpcklwd_r2r(mm1, mm1);			\
    300 	ALPHA = 0x03E0;					\
    301         movd_m2r(*(&ALPHA), mm4);			\
    302         punpcklwd_r2r(mm4, mm4);			\
    303         punpcklwd_r2r(mm4, mm4);			\
    304 	ALPHA = 0x001F;					\
    305 	movd_m2r(*(&ALPHA), mm7);			\
    306         punpcklwd_r2r(mm7, mm7);			\
    307         punpcklwd_r2r(mm7, mm7);			\
    308 	alpha &= ~(1+2+4);				\
    309         i = (Uint32)alpha | (Uint32)alpha << 16;	\
    310         movd_m2r(*(&i), mm0);				\
    311         punpckldq_r2r(mm0, mm0);			\
    312         i = ((int)(length) & 3);				\
    313         ALPHA = alpha >> 3;				\
    314 	for(; i > 0; --i) {				\
    315 	    Uint32 s = *srcp++;				\
    316 	    Uint32 d = *dstp;				\
    317 	    s = (s | s << 16) & 0x03e07c1f;		\
    318 	    d = (d | d << 16) & 0x03e07c1f;		\
    319 	    d += (s - d) * ALPHA >> 5;			\
    320 	    d &= 0x03e07c1f;				\
    321 	    *dstp++ = d | d >> 16;			\
    322 	    n++;					\
    323 	}						\
    324 	i = (int)(length) - n;				\
    325 	for(; i > 0; --i) {				\
    326 	  movq_m2r((*dstp), mm3);			\
    327 	  movq_m2r((*srcp), mm2);			\
    328 	  movq_r2r(mm2, mm5);				\
    329 	  pand_r2r(mm1 , mm5);				\
    330 	  psrlq_i2r(10, mm5);				\
    331 	  movq_r2r(mm3, mm6);				\
    332 	  pand_r2r(mm1 , mm6);				\
    333 	  psrlq_i2r(10, mm6);				\
    334 	  psubw_r2r(mm6, mm5);				\
    335 	  pmullw_r2r(mm0, mm5);				\
    336 	  psrlw_i2r(8, mm5);				\
    337 	  paddw_r2r(mm5, mm6);				\
    338 	  psllq_i2r(10, mm6);				\
    339 	  pand_r2r(mm1, mm6);				\
    340 	  movq_r2r(mm4, mm5);				\
    341 	  por_r2r(mm7, mm5);				\
    342 	  pand_r2r(mm5, mm3);				\
    343 	  por_r2r(mm6, mm3);				\
    344 	  movq_r2r(mm2, mm5);				\
    345 	  pand_r2r(mm4 , mm5);				\
    346 	  psrlq_i2r(5, mm5);				\
    347 	  movq_r2r(mm3, mm6);				\
    348 	  pand_r2r(mm4 , mm6);				\
    349 	  psrlq_i2r(5, mm6);				\
    350 	  psubw_r2r(mm6, mm5);				\
    351 	  pmullw_r2r(mm0, mm5);				\
    352 	  psrlw_i2r(8, mm5);				\
    353 	  paddw_r2r(mm5, mm6);				\
    354 	  psllq_i2r(5, mm6);				\
    355 	  pand_r2r(mm4, mm6);				\
    356 	  movq_r2r(mm1, mm5);				\
    357 	  por_r2r(mm7, mm5);				\
    358 	  pand_r2r(mm5, mm3);				\
    359 	  por_r2r(mm6, mm3);				\
    360 	  movq_r2r(mm2, mm5);				\
    361 	  pand_r2r(mm7 , mm5);				\
    362           movq_r2r(mm3, mm6);				\
    363 	  pand_r2r(mm7 , mm6);				\
    364 	  psubw_r2r(mm6, mm5);				\
    365 	  pmullw_r2r(mm0, mm5);				\
    366 	  psrlw_i2r(8, mm5);				\
    367 	  paddw_r2r(mm5, mm6);				\
    368 	  pand_r2r(mm7, mm6);				\
    369 	  movq_r2r(mm1, mm5);				\
    370 	  por_r2r(mm4, mm5);				\
    371 	  pand_r2r(mm5, mm3);				\
    372 	  por_r2r(mm6, mm3);				\
    373 	  movq_r2m(mm3, *dstp);				\
    374 	  srcp += 4;					\
    375 	  dstp += 4;					\
    376 	  i -= 3;					\
    377 	}						\
    378 	emms();						\
    379     } while(0)
    380 
    381 #endif
    382 
    383 /*
    384  * For 32bpp pixels on the form 0x00rrggbb:
    385  * If we treat the middle component separately, we can process the two
    386  * remaining in parallel. This is safe to do because of the gap to the left
    387  * of each component, so the bits from the multiplication don't collide.
    388  * This can be used for any RGB permutation of course.
    389  */
    390 #define ALPHA_BLIT32_888(to, from, length, bpp, alpha)		\
    391     do {							\
    392         int i;							\
    393 	Uint32 *src = (Uint32 *)(from);				\
    394 	Uint32 *dst = (Uint32 *)(to);				\
    395 	for(i = 0; i < (int)(length); i++) {			\
    396 	    Uint32 s = *src++;					\
    397 	    Uint32 d = *dst;					\
    398 	    Uint32 s1 = s & 0xff00ff;				\
    399 	    Uint32 d1 = d & 0xff00ff;				\
    400 	    d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff;	\
    401 	    s &= 0xff00;					\
    402 	    d &= 0xff00;					\
    403 	    d = (d + ((s - d) * alpha >> 8)) & 0xff00;		\
    404 	    *dst++ = d1 | d;					\
    405 	}							\
    406     } while(0)
    407 
    408 /*
    409  * For 16bpp pixels we can go a step further: put the middle component
    410  * in the high 16 bits of a 32 bit word, and process all three RGB
    411  * components at the same time. Since the smallest gap is here just
    412  * 5 bits, we have to scale alpha down to 5 bits as well.
    413  */
    414 #define ALPHA_BLIT16_565(to, from, length, bpp, alpha)	\
    415     do {						\
    416         int i;						\
    417 	Uint16 *src = (Uint16 *)(from);			\
    418 	Uint16 *dst = (Uint16 *)(to);			\
    419 	Uint32 ALPHA = alpha >> 3;			\
    420 	for(i = 0; i < (int)(length); i++) {		\
    421 	    Uint32 s = *src++;				\
    422 	    Uint32 d = *dst;				\
    423 	    s = (s | s << 16) & 0x07e0f81f;		\
    424 	    d = (d | d << 16) & 0x07e0f81f;		\
    425 	    d += (s - d) * ALPHA >> 5;			\
    426 	    d &= 0x07e0f81f;				\
    427 	    *dst++ = (Uint16)(d | d >> 16);			\
    428 	}						\
    429     } while(0)
    430 
    431 #define ALPHA_BLIT16_555(to, from, length, bpp, alpha)	\
    432     do {						\
    433         int i;						\
    434 	Uint16 *src = (Uint16 *)(from);			\
    435 	Uint16 *dst = (Uint16 *)(to);			\
    436 	Uint32 ALPHA = alpha >> 3;			\
    437 	for(i = 0; i < (int)(length); i++) {		\
    438 	    Uint32 s = *src++;				\
    439 	    Uint32 d = *dst;				\
    440 	    s = (s | s << 16) & 0x03e07c1f;		\
    441 	    d = (d | d << 16) & 0x03e07c1f;		\
    442 	    d += (s - d) * ALPHA >> 5;			\
    443 	    d &= 0x03e07c1f;				\
    444 	    *dst++ = (Uint16)(d | d >> 16);			\
    445 	}						\
    446     } while(0)
    447 
    448 /*
    449  * The general slow catch-all function, for remaining depths and formats
    450  */
    451 #define ALPHA_BLIT_ANY(to, from, length, bpp, alpha)			\
    452     do {								\
    453         int i;								\
    454 	Uint8 *src = from;						\
    455 	Uint8 *dst = to;						\
    456 	for(i = 0; i < (int)(length); i++) {				\
    457 	    Uint32 s, d;						\
    458 	    unsigned rs, gs, bs, rd, gd, bd;				\
    459 	    switch(bpp) {						\
    460 	    case 2:							\
    461 		s = *(Uint16 *)src;					\
    462 		d = *(Uint16 *)dst;					\
    463 		break;							\
    464 	    case 3:							\
    465 		if(SDL_BYTEORDER == SDL_BIG_ENDIAN) {			\
    466 		    s = (src[0] << 16) | (src[1] << 8) | src[2];	\
    467 		    d = (dst[0] << 16) | (dst[1] << 8) | dst[2];	\
    468 		} else {						\
    469 		    s = (src[2] << 16) | (src[1] << 8) | src[0];	\
    470 		    d = (dst[2] << 16) | (dst[1] << 8) | dst[0];	\
    471 		}							\
    472 		break;							\
    473 	    case 4:							\
    474 		s = *(Uint32 *)src;					\
    475 		d = *(Uint32 *)dst;					\
    476 		break;							\
    477 	    }								\
    478 	    RGB_FROM_PIXEL(s, fmt, rs, gs, bs);				\
    479 	    RGB_FROM_PIXEL(d, fmt, rd, gd, bd);				\
    480 	    rd += (rs - rd) * alpha >> 8;				\
    481 	    gd += (gs - gd) * alpha >> 8;				\
    482 	    bd += (bs - bd) * alpha >> 8;				\
    483 	    PIXEL_FROM_RGB(d, fmt, rd, gd, bd);				\
    484 	    switch(bpp) {						\
    485 	    case 2:							\
    486 		*(Uint16 *)dst = (Uint16)d;					\
    487 		break;							\
    488 	    case 3:							\
    489 		if(SDL_BYTEORDER == SDL_BIG_ENDIAN) {			\
    490 		    dst[0] = (Uint8)(d >> 16);					\
    491 		    dst[1] = (Uint8)(d >> 8);					\
    492 		    dst[2] = (Uint8)(d);						\
    493 		} else {						\
    494 		    dst[0] = (Uint8)d;						\
    495 		    dst[1] = (Uint8)(d >> 8);					\
    496 		    dst[2] = (Uint8)(d >> 16);					\
    497 		}							\
    498 		break;							\
    499 	    case 4:							\
    500 		*(Uint32 *)dst = d;					\
    501 		break;							\
    502 	    }								\
    503 	    src += bpp;							\
    504 	    dst += bpp;							\
    505 	}								\
    506     } while(0)
    507 
    508 #ifdef MMX_ASMBLIT
    509 
    510 #define ALPHA_BLIT32_888_50MMX(to, from, length, bpp, alpha)		\
    511     do {								\
    512 	Uint32 *srcp = (Uint32 *)(from);				\
    513 	Uint32 *dstp = (Uint32 *)(to);					\
    514         int i = 0x00fefefe;						\
    515         movd_m2r(*(&i), mm4);						\
    516         punpckldq_r2r(mm4, mm4);					\
    517         i = 0x00010101;							\
    518         movd_m2r(*(&i), mm3);						\
    519         punpckldq_r2r(mm3, mm3);					\
    520         i = (int)(length);						\
    521         if( i & 1 ) {							\
    522 	  Uint32 s = *srcp++;						\
    523 	  Uint32 d = *dstp;						\
    524 	  *dstp++ = (((s & 0x00fefefe) + (d & 0x00fefefe)) >> 1)	\
    525 		     + (s & d & 0x00010101);				\
    526 	  i--;								\
    527 	}								\
    528 	for(; i > 0; --i) {						\
    529 	    movq_m2r((*dstp), mm2); /* dst -> mm2 */			\
    530 	    movq_r2r(mm2, mm6);	/* dst -> mm6 */			\
    531 	    movq_m2r((*srcp), mm1); /* src -> mm1 */			\
    532 	    movq_r2r(mm1, mm5);	/* src -> mm5 */			\
    533 	    pand_r2r(mm4, mm6);	/* dst & 0x00fefefe -> mm6 */		\
    534 	    pand_r2r(mm4, mm5); /* src & 0x00fefefe -> mm5 */		\
    535 	    paddd_r2r(mm6, mm5); /* (dst & 0x00fefefe) + (dst & 0x00fefefe) -> mm5 */	\
    536 	    psrld_i2r(1, mm5);						\
    537 	    pand_r2r(mm1, mm2);	/* s & d -> mm2 */			\
    538 	    pand_r2r(mm3, mm2);	/* s & d & 0x00010101 -> mm2 */		\
    539 	    paddd_r2r(mm5, mm2);					\
    540 	    movq_r2m(mm2, (*dstp));					\
    541 	    dstp += 2;							\
    542 	    srcp += 2;							\
    543 	    i--;							\
    544 	}								\
    545 	emms();								\
    546     } while(0)
    547 
    548 #endif
    549 
    550 /*
    551  * Special case: 50% alpha (alpha=128)
    552  * This is treated specially because it can be optimized very well, and
    553  * since it is good for many cases of semi-translucency.
    554  * The theory is to do all three components at the same time:
    555  * First zero the lowest bit of each component, which gives us room to
    556  * add them. Then shift right and add the sum of the lowest bits.
    557  */
    558 #define ALPHA_BLIT32_888_50(to, from, length, bpp, alpha)		\
    559     do {								\
    560         int i;								\
    561 	Uint32 *src = (Uint32 *)(from);					\
    562 	Uint32 *dst = (Uint32 *)(to);					\
    563 	for(i = 0; i < (int)(length); i++) {				\
    564 	    Uint32 s = *src++;						\
    565 	    Uint32 d = *dst;						\
    566 	    *dst++ = (((s & 0x00fefefe) + (d & 0x00fefefe)) >> 1)	\
    567 		     + (s & d & 0x00010101);				\
    568 	}								\
    569     } while(0)
    570 
    571 /*
    572  * For 16bpp, we can actually blend two pixels in parallel, if we take
    573  * care to shift before we add, not after.
    574  */
    575 
    576 /* helper: blend a single 16 bit pixel at 50% */
    577 #define BLEND16_50(dst, src, mask)			\
    578     do {						\
    579 	Uint32 s = *src++;				\
    580 	Uint32 d = *dst;				\
    581 	*dst++ = (Uint16)((((s & mask) + (d & mask)) >> 1) +	\
    582 	                  (s & d & (~mask & 0xffff)));		\
    583     } while(0)
    584 
    585 /* basic 16bpp blender. mask is the pixels to keep when adding. */
    586 #define ALPHA_BLIT16_50(to, from, length, bpp, alpha, mask)		\
    587     do {								\
    588 	unsigned n = (length);						\
    589 	Uint16 *src = (Uint16 *)(from);					\
    590 	Uint16 *dst = (Uint16 *)(to);					\
    591 	if(((uintptr_t)src ^ (uintptr_t)dst) & 3) {			\
    592 	    /* source and destination not in phase, blit one by one */	\
    593 	    while(n--)							\
    594 		BLEND16_50(dst, src, mask);				\
    595 	} else {							\
    596 	    if((uintptr_t)src & 3) {					\
    597 		/* first odd pixel */					\
    598 		BLEND16_50(dst, src, mask);				\
    599 		n--;							\
    600 	    }								\
    601 	    for(; n > 1; n -= 2) {					\
    602 		Uint32 s = *(Uint32 *)src;				\
    603 		Uint32 d = *(Uint32 *)dst;				\
    604 		*(Uint32 *)dst = ((s & (mask | mask << 16)) >> 1)	\
    605 		               + ((d & (mask | mask << 16)) >> 1)	\
    606 		               + (s & d & (~(mask | mask << 16)));	\
    607 		src += 2;						\
    608 		dst += 2;						\
    609 	    }								\
    610 	    if(n)							\
    611 		BLEND16_50(dst, src, mask); /* last odd pixel */	\
    612 	}								\
    613     } while(0)
    614 
    615 #define ALPHA_BLIT16_565_50(to, from, length, bpp, alpha)	\
    616     ALPHA_BLIT16_50(to, from, length, bpp, alpha, 0xf7de)
    617 
    618 #define ALPHA_BLIT16_555_50(to, from, length, bpp, alpha)	\
    619     ALPHA_BLIT16_50(to, from, length, bpp, alpha, 0xfbde)
    620 
    621 #ifdef MMX_ASMBLIT
    622 
    623 #define CHOOSE_BLIT(blitter, alpha, fmt)				\
    624     do {								\
    625         if(alpha == 255) {						\
    626 	    switch(fmt->BytesPerPixel) {				\
    627 	    case 1: blitter(1, Uint8, OPAQUE_BLIT); break;		\
    628 	    case 2: blitter(2, Uint8, OPAQUE_BLIT); break;		\
    629 	    case 3: blitter(3, Uint8, OPAQUE_BLIT); break;		\
    630 	    case 4: blitter(4, Uint16, OPAQUE_BLIT); break;		\
    631 	    }								\
    632 	} else {							\
    633 	    switch(fmt->BytesPerPixel) {				\
    634 	    case 1:							\
    635 		/* No 8bpp alpha blitting */				\
    636 		break;							\
    637 									\
    638 	    case 2:							\
    639 		switch(fmt->Rmask | fmt->Gmask | fmt->Bmask) {		\
    640 		case 0xffff:						\
    641 		    if(fmt->Gmask == 0x07e0				\
    642 		       || fmt->Rmask == 0x07e0				\
    643 		       || fmt->Bmask == 0x07e0) {			\
    644 			if(alpha == 128)				\
    645 			    blitter(2, Uint8, ALPHA_BLIT16_565_50);	\
    646 			else {						\
    647 			    if(SDL_HasMMX())				\
    648 				blitter(2, Uint8, ALPHA_BLIT16_565MMX);	\
    649 			    else					\
    650 				blitter(2, Uint8, ALPHA_BLIT16_565);	\
    651 			}						\
    652 		    } else						\
    653 			goto general16;					\
    654 		    break;						\
    655 									\
    656 		case 0x7fff:						\
    657 		    if(fmt->Gmask == 0x03e0				\
    658 		       || fmt->Rmask == 0x03e0				\
    659 		       || fmt->Bmask == 0x03e0) {			\
    660 			if(alpha == 128)				\
    661 			    blitter(2, Uint8, ALPHA_BLIT16_555_50);	\
    662 			else {						\
    663 			    if(SDL_HasMMX())				\
    664 				blitter(2, Uint8, ALPHA_BLIT16_555MMX);	\
    665 			    else					\
    666 				blitter(2, Uint8, ALPHA_BLIT16_555);	\
    667 			}						\
    668 			break;						\
    669 		    }							\
    670 		    /* fallthrough */					\
    671 									\
    672 		default:						\
    673 		general16:						\
    674 		    blitter(2, Uint8, ALPHA_BLIT_ANY);			\
    675 		}							\
    676 		break;							\
    677 									\
    678 	    case 3:							\
    679 		blitter(3, Uint8, ALPHA_BLIT_ANY);			\
    680 		break;							\
    681 									\
    682 	    case 4:							\
    683 		if((fmt->Rmask | fmt->Gmask | fmt->Bmask) == 0x00ffffff	\
    684 		   && (fmt->Gmask == 0xff00 || fmt->Rmask == 0xff00	\
    685 		       || fmt->Bmask == 0xff00)) {			\
    686 		    if(alpha == 128)					\
    687 		    {							\
    688 			if(SDL_HasMMX())				\
    689 				blitter(4, Uint16, ALPHA_BLIT32_888_50MMX);\
    690 			else						\
    691 				blitter(4, Uint16, ALPHA_BLIT32_888_50);\
    692 		    }							\
    693 		    else						\
    694 		    {							\
    695 			if(SDL_HasMMX())				\
    696 				blitter(4, Uint16, ALPHA_BLIT32_888MMX);\
    697 			else						\
    698 				blitter(4, Uint16, ALPHA_BLIT32_888);	\
    699 		    }							\
    700 		} else							\
    701 		    blitter(4, Uint16, ALPHA_BLIT_ANY);			\
    702 		break;							\
    703 	    }								\
    704 	}								\
    705     } while(0)
    706 
    707 #else
    708 
    709 #define CHOOSE_BLIT(blitter, alpha, fmt)				\
    710     do {								\
    711         if(alpha == 255) {						\
    712 	    switch(fmt->BytesPerPixel) {				\
    713 	    case 1: blitter(1, Uint8, OPAQUE_BLIT); break;		\
    714 	    case 2: blitter(2, Uint8, OPAQUE_BLIT); break;		\
    715 	    case 3: blitter(3, Uint8, OPAQUE_BLIT); break;		\
    716 	    case 4: blitter(4, Uint16, OPAQUE_BLIT); break;		\
    717 	    }								\
    718 	} else {							\
    719 	    switch(fmt->BytesPerPixel) {				\
    720 	    case 1:							\
    721 		/* No 8bpp alpha blitting */				\
    722 		break;							\
    723 									\
    724 	    case 2:							\
    725 		switch(fmt->Rmask | fmt->Gmask | fmt->Bmask) {		\
    726 		case 0xffff:						\
    727 		    if(fmt->Gmask == 0x07e0				\
    728 		       || fmt->Rmask == 0x07e0				\
    729 		       || fmt->Bmask == 0x07e0) {			\
    730 			if(alpha == 128)				\
    731 			    blitter(2, Uint8, ALPHA_BLIT16_565_50);	\
    732 			else {						\
    733 			    blitter(2, Uint8, ALPHA_BLIT16_565);	\
    734 			}						\
    735 		    } else						\
    736 			goto general16;					\
    737 		    break;						\
    738 									\
    739 		case 0x7fff:						\
    740 		    if(fmt->Gmask == 0x03e0				\
    741 		       || fmt->Rmask == 0x03e0				\
    742 		       || fmt->Bmask == 0x03e0) {			\
    743 			if(alpha == 128)				\
    744 			    blitter(2, Uint8, ALPHA_BLIT16_555_50);	\
    745 			else {						\
    746 			    blitter(2, Uint8, ALPHA_BLIT16_555);	\
    747 			}						\
    748 			break;						\
    749 		    }							\
    750 		    /* fallthrough */					\
    751 									\
    752 		default:						\
    753 		general16:						\
    754 		    blitter(2, Uint8, ALPHA_BLIT_ANY);			\
    755 		}							\
    756 		break;							\
    757 									\
    758 	    case 3:							\
    759 		blitter(3, Uint8, ALPHA_BLIT_ANY);			\
    760 		break;							\
    761 									\
    762 	    case 4:							\
    763 		if((fmt->Rmask | fmt->Gmask | fmt->Bmask) == 0x00ffffff	\
    764 		   && (fmt->Gmask == 0xff00 || fmt->Rmask == 0xff00	\
    765 		       || fmt->Bmask == 0xff00)) {			\
    766 		    if(alpha == 128)					\
    767 			blitter(4, Uint16, ALPHA_BLIT32_888_50);	\
    768 		    else						\
    769 			blitter(4, Uint16, ALPHA_BLIT32_888);		\
    770 		} else							\
    771 		    blitter(4, Uint16, ALPHA_BLIT_ANY);			\
    772 		break;							\
    773 	    }								\
    774 	}								\
    775     } while(0)
    776 
    777 #endif
    778 
    779 /*
    780  * This takes care of the case when the surface is clipped on the left and/or
    781  * right. Top clipping has already been taken care of.
    782  */
    783 static void RLEClipBlit(int w, Uint8 *srcbuf, SDL_Surface *dst,
    784 			Uint8 *dstbuf, SDL_Rect *srcrect, unsigned alpha)
    785 {
    786     SDL_PixelFormat *fmt = dst->format;
    787 
    788 #define RLECLIPBLIT(bpp, Type, do_blit)					   \
    789     do {								   \
    790 	int linecount = srcrect->h;					   \
    791 	int ofs = 0;							   \
    792 	int left = srcrect->x;						   \
    793 	int right = left + srcrect->w;					   \
    794 	dstbuf -= left * bpp;						   \
    795 	for(;;) {							   \
    796 	    int run;							   \
    797 	    ofs += *(Type *)srcbuf;					   \
    798 	    run = ((Type *)srcbuf)[1];					   \
    799 	    srcbuf += 2 * sizeof(Type);					   \
    800 	    if(run) {							   \
    801 		/* clip to left and right borders */			   \
    802 		if(ofs < right) {					   \
    803 		    int start = 0;					   \
    804 		    int len = run;					   \
    805 		    int startcol;					   \
    806 		    if(left - ofs > 0) {				   \
    807 			start = left - ofs;				   \
    808 			len -= start;					   \
    809 			if(len <= 0)					   \
    810 			    goto nocopy ## bpp ## do_blit;		   \
    811 		    }							   \
    812 		    startcol = ofs + start;				   \
    813 		    if(len > right - startcol)				   \
    814 			len = right - startcol;				   \
    815 		    do_blit(dstbuf + startcol * bpp, srcbuf + start * bpp, \
    816 			    len, bpp, alpha);				   \
    817 		}							   \
    818 	    nocopy ## bpp ## do_blit:					   \
    819 		srcbuf += run * bpp;					   \
    820 		ofs += run;						   \
    821 	    } else if(!ofs)						   \
    822 		break;							   \
    823 	    if(ofs == w) {						   \
    824 		ofs = 0;						   \
    825 		dstbuf += dst->pitch;					   \
    826 		if(!--linecount)					   \
    827 		    break;						   \
    828 	    }								   \
    829 	}								   \
    830     } while(0)
    831 
    832     CHOOSE_BLIT(RLECLIPBLIT, alpha, fmt);
    833 
    834 #undef RLECLIPBLIT
    835 
    836 }
    837 
    838 
    839 /* blit a colorkeyed RLE surface */
    840 int SDL_RLEBlit(SDL_Surface *src, SDL_Rect *srcrect,
    841 		SDL_Surface *dst, SDL_Rect *dstrect)
    842 {
    843 	Uint8 *dstbuf;
    844 	Uint8 *srcbuf;
    845 	int x, y;
    846 	int w = src->w;
    847 	unsigned alpha;
    848 
    849 	/* Lock the destination if necessary */
    850 	if ( SDL_MUSTLOCK(dst) ) {
    851 		if ( SDL_LockSurface(dst) < 0 ) {
    852 			return(-1);
    853 		}
    854 	}
    855 
    856 	/* Set up the source and destination pointers */
    857 	x = dstrect->x;
    858 	y = dstrect->y;
    859 	dstbuf = (Uint8 *)dst->pixels
    860 	         + y * dst->pitch + x * src->format->BytesPerPixel;
    861 	srcbuf = (Uint8 *)src->map->sw_data->aux_data;
    862 
    863 	{
    864 	    /* skip lines at the top if neccessary */
    865 	    int vskip = srcrect->y;
    866 	    int ofs = 0;
    867 	    if(vskip) {
    868 
    869 #define RLESKIP(bpp, Type)			\
    870 		for(;;) {			\
    871 		    int run;			\
    872 		    ofs += *(Type *)srcbuf;	\
    873 		    run = ((Type *)srcbuf)[1];	\
    874 		    srcbuf += sizeof(Type) * 2;	\
    875 		    if(run) {			\
    876 			srcbuf += run * bpp;	\
    877 			ofs += run;		\
    878 		    } else if(!ofs)		\
    879 			goto done;		\
    880 		    if(ofs == w) {		\
    881 			ofs = 0;		\
    882 			if(!--vskip)		\
    883 			    break;		\
    884 		    }				\
    885 		}
    886 
    887 		switch(src->format->BytesPerPixel) {
    888 		case 1: RLESKIP(1, Uint8); break;
    889 		case 2: RLESKIP(2, Uint8); break;
    890 		case 3: RLESKIP(3, Uint8); break;
    891 		case 4: RLESKIP(4, Uint16); break;
    892 		}
    893 
    894 #undef RLESKIP
    895 
    896 	    }
    897 	}
    898 
    899 	alpha = (src->flags & SDL_SRCALPHA) == SDL_SRCALPHA
    900 	        ? src->format->alpha : 255;
    901 	/* if left or right edge clipping needed, call clip blit */
    902 	if ( srcrect->x || srcrect->w != src->w ) {
    903 	    RLEClipBlit(w, srcbuf, dst, dstbuf, srcrect, alpha);
    904 	} else {
    905 	    SDL_PixelFormat *fmt = src->format;
    906 
    907 #define RLEBLIT(bpp, Type, do_blit)					      \
    908 	    do {							      \
    909 		int linecount = srcrect->h;				      \
    910 		int ofs = 0;						      \
    911 		for(;;) {						      \
    912 		    unsigned run;					      \
    913 		    ofs += *(Type *)srcbuf;				      \
    914 		    run = ((Type *)srcbuf)[1];				      \
    915 		    srcbuf += 2 * sizeof(Type);				      \
    916 		    if(run) {						      \
    917 			do_blit(dstbuf + ofs * bpp, srcbuf, run, bpp, alpha); \
    918 			srcbuf += run * bpp;				      \
    919 			ofs += run;					      \
    920 		    } else if(!ofs)					      \
    921 			break;						      \
    922 		    if(ofs == w) {					      \
    923 			ofs = 0;					      \
    924 			dstbuf += dst->pitch;				      \
    925 			if(!--linecount)				      \
    926 			    break;					      \
    927 		    }							      \
    928 		}							      \
    929 	    } while(0)
    930 
    931 	    CHOOSE_BLIT(RLEBLIT, alpha, fmt);
    932 
    933 #undef RLEBLIT
    934 	}
    935 
    936 done:
    937 	/* Unlock the destination if necessary */
    938 	if ( SDL_MUSTLOCK(dst) ) {
    939 		SDL_UnlockSurface(dst);
    940 	}
    941 	return(0);
    942 }
    943 
    944 #undef OPAQUE_BLIT
    945 
    946 /*
    947  * Per-pixel blitting macros for translucent pixels:
    948  * These use the same techniques as the per-surface blitting macros
    949  */
    950 
    951 /*
    952  * For 32bpp pixels, we have made sure the alpha is stored in the top
    953  * 8 bits, so proceed as usual
    954  */
    955 #define BLIT_TRANSL_888(src, dst)				\
    956     do {							\
    957         Uint32 s = src;						\
    958 	Uint32 d = dst;						\
    959 	unsigned alpha = s >> 24;				\
    960 	Uint32 s1 = s & 0xff00ff;				\
    961 	Uint32 d1 = d & 0xff00ff;				\
    962 	d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff;	\
    963 	s &= 0xff00;						\
    964 	d &= 0xff00;						\
    965 	d = (d + ((s - d) * alpha >> 8)) & 0xff00;		\
    966 	dst = d1 | d;						\
    967     } while(0)
    968 
    969 /*
    970  * For 16bpp pixels, we have stored the 5 most significant alpha bits in
    971  * bits 5-10. As before, we can process all 3 RGB components at the same time.
    972  */
    973 #define BLIT_TRANSL_565(src, dst)		\
    974     do {					\
    975 	Uint32 s = src;				\
    976 	Uint32 d = dst;				\
    977 	unsigned alpha = (s & 0x3e0) >> 5;	\
    978 	s &= 0x07e0f81f;			\
    979 	d = (d | d << 16) & 0x07e0f81f;		\
    980 	d += (s - d) * alpha >> 5;		\
    981 	d &= 0x07e0f81f;			\
    982 	dst = (Uint16)(d | d >> 16);			\
    983     } while(0)
    984 
    985 #define BLIT_TRANSL_555(src, dst)		\
    986     do {					\
    987 	Uint32 s = src;				\
    988 	Uint32 d = dst;				\
    989 	unsigned alpha = (s & 0x3e0) >> 5;	\
    990 	s &= 0x03e07c1f;			\
    991 	d = (d | d << 16) & 0x03e07c1f;		\
    992 	d += (s - d) * alpha >> 5;		\
    993 	d &= 0x03e07c1f;			\
    994 	dst = (Uint16)(d | d >> 16);			\
    995     } while(0)
    996 
    997 /* used to save the destination format in the encoding. Designed to be
    998    macro-compatible with SDL_PixelFormat but without the unneeded fields */
    999 typedef struct {
   1000 	Uint8  BytesPerPixel;
   1001 	Uint8  Rloss;
   1002 	Uint8  Gloss;
   1003 	Uint8  Bloss;
   1004 	Uint8  Rshift;
   1005 	Uint8  Gshift;
   1006 	Uint8  Bshift;
   1007 	Uint8  Ashift;
   1008 	Uint32 Rmask;
   1009 	Uint32 Gmask;
   1010 	Uint32 Bmask;
   1011 	Uint32 Amask;
   1012 } RLEDestFormat;
   1013 
   1014 /* blit a pixel-alpha RLE surface clipped at the right and/or left edges */
   1015 static void RLEAlphaClipBlit(int w, Uint8 *srcbuf, SDL_Surface *dst,
   1016 			     Uint8 *dstbuf, SDL_Rect *srcrect)
   1017 {
   1018     SDL_PixelFormat *df = dst->format;
   1019     /*
   1020      * clipped blitter: Ptype is the destination pixel type,
   1021      * Ctype the translucent count type, and do_blend the macro
   1022      * to blend one pixel.
   1023      */
   1024 #define RLEALPHACLIPBLIT(Ptype, Ctype, do_blend)			  \
   1025     do {								  \
   1026 	int linecount = srcrect->h;					  \
   1027 	int left = srcrect->x;						  \
   1028 	int right = left + srcrect->w;					  \
   1029 	dstbuf -= left * sizeof(Ptype);					  \
   1030 	do {								  \
   1031 	    int ofs = 0;						  \
   1032 	    /* blit opaque pixels on one line */			  \
   1033 	    do {							  \
   1034 		unsigned run;						  \
   1035 		ofs += ((Ctype *)srcbuf)[0];				  \
   1036 		run = ((Ctype *)srcbuf)[1];				  \
   1037 		srcbuf += 2 * sizeof(Ctype);				  \
   1038 		if(run) {						  \
   1039 		    /* clip to left and right borders */		  \
   1040 		    int cofs = ofs;					  \
   1041 		    int crun = run;					  \
   1042 		    if(left - cofs > 0) {				  \
   1043 			crun -= left - cofs;				  \
   1044 			cofs = left;					  \
   1045 		    }							  \
   1046 		    if(crun > right - cofs)				  \
   1047 			crun = right - cofs;				  \
   1048 		    if(crun > 0)					  \
   1049 			PIXEL_COPY(dstbuf + cofs * sizeof(Ptype),	  \
   1050 				   srcbuf + (cofs - ofs) * sizeof(Ptype), \
   1051 				   (unsigned)crun, sizeof(Ptype));	  \
   1052 		    srcbuf += run * sizeof(Ptype);			  \
   1053 		    ofs += run;						  \
   1054 		} else if(!ofs)						  \
   1055 		    return;						  \
   1056 	    } while(ofs < w);						  \
   1057 	    /* skip padding if necessary */				  \
   1058 	    if(sizeof(Ptype) == 2)					  \
   1059 		srcbuf += (uintptr_t)srcbuf & 2;			  \
   1060 	    /* blit translucent pixels on the same line */		  \
   1061 	    ofs = 0;							  \
   1062 	    do {							  \
   1063 		unsigned run;						  \
   1064 		ofs += ((Uint16 *)srcbuf)[0];				  \
   1065 		run = ((Uint16 *)srcbuf)[1];				  \
   1066 		srcbuf += 4;						  \
   1067 		if(run) {						  \
   1068 		    /* clip to left and right borders */		  \
   1069 		    int cofs = ofs;					  \
   1070 		    int crun = run;					  \
   1071 		    if(left - cofs > 0) {				  \
   1072 			crun -= left - cofs;				  \
   1073 			cofs = left;					  \
   1074 		    }							  \
   1075 		    if(crun > right - cofs)				  \
   1076 			crun = right - cofs;				  \
   1077 		    if(crun > 0) {					  \
   1078 			Ptype *dst = (Ptype *)dstbuf + cofs;		  \
   1079 			Uint32 *src = (Uint32 *)srcbuf + (cofs - ofs);	  \
   1080 			int i;						  \
   1081 			for(i = 0; i < crun; i++)			  \
   1082 			    do_blend(src[i], dst[i]);			  \
   1083 		    }							  \
   1084 		    srcbuf += run * 4;					  \
   1085 		    ofs += run;						  \
   1086 		}							  \
   1087 	    } while(ofs < w);						  \
   1088 	    dstbuf += dst->pitch;					  \
   1089 	} while(--linecount);						  \
   1090     } while(0)
   1091 
   1092     switch(df->BytesPerPixel) {
   1093     case 2:
   1094 	if(df->Gmask == 0x07e0 || df->Rmask == 0x07e0
   1095 	   || df->Bmask == 0x07e0)
   1096 	    RLEALPHACLIPBLIT(Uint16, Uint8, BLIT_TRANSL_565);
   1097 	else
   1098 	    RLEALPHACLIPBLIT(Uint16, Uint8, BLIT_TRANSL_555);
   1099 	break;
   1100     case 4:
   1101 	RLEALPHACLIPBLIT(Uint32, Uint16, BLIT_TRANSL_888);
   1102 	break;
   1103     }
   1104 }
   1105 
   1106 /* blit a pixel-alpha RLE surface */
   1107 int SDL_RLEAlphaBlit(SDL_Surface *src, SDL_Rect *srcrect,
   1108 		     SDL_Surface *dst, SDL_Rect *dstrect)
   1109 {
   1110     int x, y;
   1111     int w = src->w;
   1112     Uint8 *srcbuf, *dstbuf;
   1113     SDL_PixelFormat *df = dst->format;
   1114 
   1115     /* Lock the destination if necessary */
   1116     if ( SDL_MUSTLOCK(dst) ) {
   1117 	if ( SDL_LockSurface(dst) < 0 ) {
   1118 	    return -1;
   1119 	}
   1120     }
   1121 
   1122     x = dstrect->x;
   1123     y = dstrect->y;
   1124     dstbuf = (Uint8 *)dst->pixels
   1125 	     + y * dst->pitch + x * df->BytesPerPixel;
   1126     srcbuf = (Uint8 *)src->map->sw_data->aux_data + sizeof(RLEDestFormat);
   1127 
   1128     {
   1129 	/* skip lines at the top if necessary */
   1130 	int vskip = srcrect->y;
   1131 	if(vskip) {
   1132 	    int ofs;
   1133 	    if(df->BytesPerPixel == 2) {
   1134 		/* the 16/32 interleaved format */
   1135 		do {
   1136 		    /* skip opaque line */
   1137 		    ofs = 0;
   1138 		    do {
   1139 			int run;
   1140 			ofs += srcbuf[0];
   1141 			run = srcbuf[1];
   1142 			srcbuf += 2;
   1143 			if(run) {
   1144 			    srcbuf += 2 * run;
   1145 			    ofs += run;
   1146 			} else if(!ofs)
   1147 			    goto done;
   1148 		    } while(ofs < w);
   1149 
   1150 		    /* skip padding */
   1151 		    srcbuf += (uintptr_t)srcbuf & 2;
   1152 
   1153 		    /* skip translucent line */
   1154 		    ofs = 0;
   1155 		    do {
   1156 			int run;
   1157 			ofs += ((Uint16 *)srcbuf)[0];
   1158 			run = ((Uint16 *)srcbuf)[1];
   1159 			srcbuf += 4 * (run + 1);
   1160 			ofs += run;
   1161 		    } while(ofs < w);
   1162 		} while(--vskip);
   1163 	    } else {
   1164 		/* the 32/32 interleaved format */
   1165 		vskip <<= 1;	/* opaque and translucent have same format */
   1166 		do {
   1167 		    ofs = 0;
   1168 		    do {
   1169 			int run;
   1170 			ofs += ((Uint16 *)srcbuf)[0];
   1171 			run = ((Uint16 *)srcbuf)[1];
   1172 			srcbuf += 4;
   1173 			if(run) {
   1174 			    srcbuf += 4 * run;
   1175 			    ofs += run;
   1176 			} else if(!ofs)
   1177 			    goto done;
   1178 		    } while(ofs < w);
   1179 		} while(--vskip);
   1180 	    }
   1181 	}
   1182     }
   1183 
   1184     /* if left or right edge clipping needed, call clip blit */
   1185     if(srcrect->x || srcrect->w != src->w) {
   1186 	RLEAlphaClipBlit(w, srcbuf, dst, dstbuf, srcrect);
   1187     } else {
   1188 
   1189 	/*
   1190 	 * non-clipped blitter. Ptype is the destination pixel type,
   1191 	 * Ctype the translucent count type, and do_blend the
   1192 	 * macro to blend one pixel.
   1193 	 */
   1194 #define RLEALPHABLIT(Ptype, Ctype, do_blend)				 \
   1195 	do {								 \
   1196 	    int linecount = srcrect->h;					 \
   1197 	    do {							 \
   1198 		int ofs = 0;						 \
   1199 		/* blit opaque pixels on one line */			 \
   1200 		do {							 \
   1201 		    unsigned run;					 \
   1202 		    ofs += ((Ctype *)srcbuf)[0];			 \
   1203 		    run = ((Ctype *)srcbuf)[1];				 \
   1204 		    srcbuf += 2 * sizeof(Ctype);			 \
   1205 		    if(run) {						 \
   1206 			PIXEL_COPY(dstbuf + ofs * sizeof(Ptype), srcbuf, \
   1207 				   run, sizeof(Ptype));			 \
   1208 			srcbuf += run * sizeof(Ptype);			 \
   1209 			ofs += run;					 \
   1210 		    } else if(!ofs)					 \
   1211 			goto done;					 \
   1212 		} while(ofs < w);					 \
   1213 		/* skip padding if necessary */				 \
   1214 		if(sizeof(Ptype) == 2)					 \
   1215 		    srcbuf += (uintptr_t)srcbuf & 2;		 	 \
   1216 		/* blit translucent pixels on the same line */		 \
   1217 		ofs = 0;						 \
   1218 		do {							 \
   1219 		    unsigned run;					 \
   1220 		    ofs += ((Uint16 *)srcbuf)[0];			 \
   1221 		    run = ((Uint16 *)srcbuf)[1];			 \
   1222 		    srcbuf += 4;					 \
   1223 		    if(run) {						 \
   1224 			Ptype *dst = (Ptype *)dstbuf + ofs;		 \
   1225 			unsigned i;					 \
   1226 			for(i = 0; i < run; i++) {			 \
   1227 			    Uint32 src = *(Uint32 *)srcbuf;		 \
   1228 			    do_blend(src, *dst);			 \
   1229 			    srcbuf += 4;				 \
   1230 			    dst++;					 \
   1231 			}						 \
   1232 			ofs += run;					 \
   1233 		    }							 \
   1234 		} while(ofs < w);					 \
   1235 		dstbuf += dst->pitch;					 \
   1236 	    } while(--linecount);					 \
   1237 	} while(0)
   1238 
   1239 	switch(df->BytesPerPixel) {
   1240 	case 2:
   1241 	    if(df->Gmask == 0x07e0 || df->Rmask == 0x07e0
   1242 	       || df->Bmask == 0x07e0)
   1243 		RLEALPHABLIT(Uint16, Uint8, BLIT_TRANSL_565);
   1244 	    else
   1245 		RLEALPHABLIT(Uint16, Uint8, BLIT_TRANSL_555);
   1246 	    break;
   1247 	case 4:
   1248 	    RLEALPHABLIT(Uint32, Uint16, BLIT_TRANSL_888);
   1249 	    break;
   1250 	}
   1251     }
   1252 
   1253  done:
   1254     /* Unlock the destination if necessary */
   1255     if ( SDL_MUSTLOCK(dst) ) {
   1256 	SDL_UnlockSurface(dst);
   1257     }
   1258     return 0;
   1259 }
   1260 
   1261 /*
   1262  * Auxiliary functions:
   1263  * The encoding functions take 32bpp rgb + a, and
   1264  * return the number of bytes copied to the destination.
   1265  * The decoding functions copy to 32bpp rgb + a, and
   1266  * return the number of bytes copied from the source.
   1267  * These are only used in the encoder and un-RLE code and are therefore not
   1268  * highly optimised.
   1269  */
   1270 
   1271 /* encode 32bpp rgb + a into 16bpp rgb, losing alpha */
   1272 static int copy_opaque_16(void *dst, Uint32 *src, int n,
   1273 			  SDL_PixelFormat *sfmt, SDL_PixelFormat *dfmt)
   1274 {
   1275     int i;
   1276     Uint16 *d = dst;
   1277     for(i = 0; i < n; i++) {
   1278 	unsigned r, g, b;
   1279 	RGB_FROM_PIXEL(*src, sfmt, r, g, b);
   1280 	PIXEL_FROM_RGB(*d, dfmt, r, g, b);
   1281 	src++;
   1282 	d++;
   1283     }
   1284     return n * 2;
   1285 }
   1286 
   1287 /* decode opaque pixels from 16bpp to 32bpp rgb + a */
   1288 static int uncopy_opaque_16(Uint32 *dst, void *src, int n,
   1289 			    RLEDestFormat *sfmt, SDL_PixelFormat *dfmt)
   1290 {
   1291     int i;
   1292     Uint16 *s = src;
   1293     unsigned alpha = dfmt->Amask ? 255 : 0;
   1294     for(i = 0; i < n; i++) {
   1295 	unsigned r, g, b;
   1296 	RGB_FROM_PIXEL(*s, sfmt, r, g, b);
   1297 	PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, alpha);
   1298 	s++;
   1299 	dst++;
   1300     }
   1301     return n * 2;
   1302 }
   1303 
   1304 
   1305 
   1306 /* encode 32bpp rgb + a into 32bpp G0RAB format for blitting into 565 */
   1307 static int copy_transl_565(void *dst, Uint32 *src, int n,
   1308 			   SDL_PixelFormat *sfmt, SDL_PixelFormat *dfmt)
   1309 {
   1310     int i;
   1311     Uint32 *d = dst;
   1312     for(i = 0; i < n; i++) {
   1313 	unsigned r, g, b, a;
   1314 	Uint16 pix;
   1315 	RGBA_FROM_8888(*src, sfmt, r, g, b, a);
   1316 	PIXEL_FROM_RGB(pix, dfmt, r, g, b);
   1317 	*d = ((pix & 0x7e0) << 16) | (pix & 0xf81f) | ((a << 2) & 0x7e0);
   1318 	src++;
   1319 	d++;
   1320     }
   1321     return n * 4;
   1322 }
   1323 
   1324 /* encode 32bpp rgb + a into 32bpp G0RAB format for blitting into 555 */
   1325 static int copy_transl_555(void *dst, Uint32 *src, int n,
   1326 			   SDL_PixelFormat *sfmt, SDL_PixelFormat *dfmt)
   1327 {
   1328     int i;
   1329     Uint32 *d = dst;
   1330     for(i = 0; i < n; i++) {
   1331 	unsigned r, g, b, a;
   1332 	Uint16 pix;
   1333 	RGBA_FROM_8888(*src, sfmt, r, g, b, a);
   1334 	PIXEL_FROM_RGB(pix, dfmt, r, g, b);
   1335 	*d = ((pix & 0x3e0) << 16) | (pix & 0xfc1f) | ((a << 2) & 0x3e0);
   1336 	src++;
   1337 	d++;
   1338     }
   1339     return n * 4;
   1340 }
   1341 
   1342 /* decode translucent pixels from 32bpp GORAB to 32bpp rgb + a */
   1343 static int uncopy_transl_16(Uint32 *dst, void *src, int n,
   1344 			    RLEDestFormat *sfmt, SDL_PixelFormat *dfmt)
   1345 {
   1346     int i;
   1347     Uint32 *s = src;
   1348     for(i = 0; i < n; i++) {
   1349 	unsigned r, g, b, a;
   1350 	Uint32 pix = *s++;
   1351 	a = (pix & 0x3e0) >> 2;
   1352 	pix = (pix & ~0x3e0) | pix >> 16;
   1353 	RGB_FROM_PIXEL(pix, sfmt, r, g, b);
   1354 	PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, a);
   1355 	dst++;
   1356     }
   1357     return n * 4;
   1358 }
   1359 
   1360 /* encode 32bpp rgba into 32bpp rgba, keeping alpha (dual purpose) */
   1361 static int copy_32(void *dst, Uint32 *src, int n,
   1362 		   SDL_PixelFormat *sfmt, SDL_PixelFormat *dfmt)
   1363 {
   1364     int i;
   1365     Uint32 *d = dst;
   1366     for(i = 0; i < n; i++) {
   1367 	unsigned r, g, b, a;
   1368 	Uint32 pixel;
   1369 	RGBA_FROM_8888(*src, sfmt, r, g, b, a);
   1370 	PIXEL_FROM_RGB(pixel, dfmt, r, g, b);
   1371 	*d++ = pixel | a << 24;
   1372 	src++;
   1373     }
   1374     return n * 4;
   1375 }
   1376 
   1377 /* decode 32bpp rgba into 32bpp rgba, keeping alpha (dual purpose) */
   1378 static int uncopy_32(Uint32 *dst, void *src, int n,
   1379 		     RLEDestFormat *sfmt, SDL_PixelFormat *dfmt)
   1380 {
   1381     int i;
   1382     Uint32 *s = src;
   1383     for(i = 0; i < n; i++) {
   1384 	unsigned r, g, b, a;
   1385 	Uint32 pixel = *s++;
   1386 	RGB_FROM_PIXEL(pixel, sfmt, r, g, b);
   1387 	a = pixel >> 24;
   1388 	PIXEL_FROM_RGBA(*dst, dfmt, r, g, b, a);
   1389 	dst++;
   1390     }
   1391     return n * 4;
   1392 }
   1393 
   1394 #define ISOPAQUE(pixel, fmt) ((((pixel) & fmt->Amask) >> fmt->Ashift) == 255)
   1395 
   1396 #define ISTRANSL(pixel, fmt)	\
   1397     ((unsigned)((((pixel) & fmt->Amask) >> fmt->Ashift) - 1U) < 254U)
   1398 
   1399 /* convert surface to be quickly alpha-blittable onto dest, if possible */
   1400 static int RLEAlphaSurface(SDL_Surface *surface)
   1401 {
   1402     SDL_Surface *dest;
   1403     SDL_PixelFormat *df;
   1404     int maxsize = 0;
   1405     int max_opaque_run;
   1406     int max_transl_run = 65535;
   1407     unsigned masksum;
   1408     Uint8 *rlebuf, *dst;
   1409     int (*copy_opaque)(void *, Uint32 *, int,
   1410 		       SDL_PixelFormat *, SDL_PixelFormat *);
   1411     int (*copy_transl)(void *, Uint32 *, int,
   1412 		       SDL_PixelFormat *, SDL_PixelFormat *);
   1413 
   1414     dest = surface->map->dst;
   1415     if(!dest)
   1416 	return -1;
   1417     df = dest->format;
   1418     if(surface->format->BitsPerPixel != 32)
   1419 	return -1;		/* only 32bpp source supported */
   1420 
   1421     /* find out whether the destination is one we support,
   1422        and determine the max size of the encoded result */
   1423     masksum = df->Rmask | df->Gmask | df->Bmask;
   1424     switch(df->BytesPerPixel) {
   1425     case 2:
   1426 	/* 16bpp: only support 565 and 555 formats */
   1427 	switch(masksum) {
   1428 	case 0xffff:
   1429 	    if(df->Gmask == 0x07e0
   1430 	       || df->Rmask == 0x07e0 || df->Bmask == 0x07e0) {
   1431 		copy_opaque = copy_opaque_16;
   1432 		copy_transl = copy_transl_565;
   1433 	    } else
   1434 		return -1;
   1435 	    break;
   1436 	case 0x7fff:
   1437 	    if(df->Gmask == 0x03e0
   1438 	       || df->Rmask == 0x03e0 || df->Bmask == 0x03e0) {
   1439 		copy_opaque = copy_opaque_16;
   1440 		copy_transl = copy_transl_555;
   1441 	    } else
   1442 		return -1;
   1443 	    break;
   1444 	default:
   1445 	    return -1;
   1446 	}
   1447 	max_opaque_run = 255;	/* runs stored as bytes */
   1448 
   1449 	/* worst case is alternating opaque and translucent pixels,
   1450 	   with room for alignment padding between lines */
   1451 	maxsize = surface->h * (2 + (4 + 2) * (surface->w + 1)) + 2;
   1452 	break;
   1453     case 4:
   1454 	if(masksum != 0x00ffffff)
   1455 	    return -1;		/* requires unused high byte */
   1456 	copy_opaque = copy_32;
   1457 	copy_transl = copy_32;
   1458 	max_opaque_run = 255;	/* runs stored as short ints */
   1459 
   1460 	/* worst case is alternating opaque and translucent pixels */
   1461 	maxsize = surface->h * 2 * 4 * (surface->w + 1) + 4;
   1462 	break;
   1463     default:
   1464 	return -1;		/* anything else unsupported right now */
   1465     }
   1466 
   1467     maxsize += sizeof(RLEDestFormat);
   1468     rlebuf = (Uint8 *)SDL_malloc(maxsize);
   1469     if(!rlebuf) {
   1470 	SDL_OutOfMemory();
   1471 	return -1;
   1472     }
   1473     {
   1474 	/* save the destination format so we can undo the encoding later */
   1475 	RLEDestFormat *r = (RLEDestFormat *)rlebuf;
   1476 	r->BytesPerPixel = df->BytesPerPixel;
   1477 	r->Rloss = df->Rloss;
   1478 	r->Gloss = df->Gloss;
   1479 	r->Bloss = df->Bloss;
   1480 	r->Rshift = df->Rshift;
   1481 	r->Gshift = df->Gshift;
   1482 	r->Bshift = df->Bshift;
   1483 	r->Ashift = df->Ashift;
   1484 	r->Rmask = df->Rmask;
   1485 	r->Gmask = df->Gmask;
   1486 	r->Bmask = df->Bmask;
   1487 	r->Amask = df->Amask;
   1488     }
   1489     dst = rlebuf + sizeof(RLEDestFormat);
   1490 
   1491     /* Do the actual encoding */
   1492     {
   1493 	int x, y;
   1494 	int h = surface->h, w = surface->w;
   1495 	SDL_PixelFormat *sf = surface->format;
   1496 	Uint32 *src = (Uint32 *)surface->pixels;
   1497 	Uint8 *lastline = dst;	/* end of last non-blank line */
   1498 
   1499 	/* opaque counts are 8 or 16 bits, depending on target depth */
   1500 #define ADD_OPAQUE_COUNTS(n, m)			\
   1501 	if(df->BytesPerPixel == 4) {		\
   1502 	    ((Uint16 *)dst)[0] = n;		\
   1503 	    ((Uint16 *)dst)[1] = m;		\
   1504 	    dst += 4;				\
   1505 	} else {				\
   1506 	    dst[0] = n;				\
   1507 	    dst[1] = m;				\
   1508 	    dst += 2;				\
   1509 	}
   1510 
   1511 	/* translucent counts are always 16 bit */
   1512 #define ADD_TRANSL_COUNTS(n, m)		\
   1513 	(((Uint16 *)dst)[0] = n, ((Uint16 *)dst)[1] = m, dst += 4)
   1514 
   1515 	for(y = 0; y < h; y++) {
   1516 	    int runstart, skipstart;
   1517 	    int blankline = 0;
   1518 	    /* First encode all opaque pixels of a scan line */
   1519 	    x = 0;
   1520 	    do {
   1521 		int run, skip, len;
   1522 		skipstart = x;
   1523 		while(x < w && !ISOPAQUE(src[x], sf))
   1524 		    x++;
   1525 		runstart = x;
   1526 		while(x < w && ISOPAQUE(src[x], sf))
   1527 		    x++;
   1528 		skip = runstart - skipstart;
   1529 		if(skip == w)
   1530 		    blankline = 1;
   1531 		run = x - runstart;
   1532 		while(skip > max_opaque_run) {
   1533 		    ADD_OPAQUE_COUNTS(max_opaque_run, 0);
   1534 		    skip -= max_opaque_run;
   1535 		}
   1536 		len = MIN(run, max_opaque_run);
   1537 		ADD_OPAQUE_COUNTS(skip, len);
   1538 		dst += copy_opaque(dst, src + runstart, len, sf, df);
   1539 		runstart += len;
   1540 		run -= len;
   1541 		while(run) {
   1542 		    len = MIN(run, max_opaque_run);
   1543 		    ADD_OPAQUE_COUNTS(0, len);
   1544 		    dst += copy_opaque(dst, src + runstart, len, sf, df);
   1545 		    runstart += len;
   1546 		    run -= len;
   1547 		}
   1548 	    } while(x < w);
   1549 
   1550 	    /* Make sure the next output address is 32-bit aligned */
   1551 	    dst += (uintptr_t)dst & 2;
   1552 
   1553 	    /* Next, encode all translucent pixels of the same scan line */
   1554 	    x = 0;
   1555 	    do {
   1556 		int run, skip, len;
   1557 		skipstart = x;
   1558 		while(x < w && !ISTRANSL(src[x], sf))
   1559 		    x++;
   1560 		runstart = x;
   1561 		while(x < w && ISTRANSL(src[x], sf))
   1562 		    x++;
   1563 		skip = runstart - skipstart;
   1564 		blankline &= (skip == w);
   1565 		run = x - runstart;
   1566 		while(skip > max_transl_run) {
   1567 		    ADD_TRANSL_COUNTS(max_transl_run, 0);
   1568 		    skip -= max_transl_run;
   1569 		}
   1570 		len = MIN(run, max_transl_run);
   1571 		ADD_TRANSL_COUNTS(skip, len);
   1572 		dst += copy_transl(dst, src + runstart, len, sf, df);
   1573 		runstart += len;
   1574 		run -= len;
   1575 		while(run) {
   1576 		    len = MIN(run, max_transl_run);
   1577 		    ADD_TRANSL_COUNTS(0, len);
   1578 		    dst += copy_transl(dst, src + runstart, len, sf, df);
   1579 		    runstart += len;
   1580 		    run -= len;
   1581 		}
   1582 		if(!blankline)
   1583 		    lastline = dst;
   1584 	    } while(x < w);
   1585 
   1586 	    src += surface->pitch >> 2;
   1587 	}
   1588 	dst = lastline;		/* back up past trailing blank lines */
   1589 	ADD_OPAQUE_COUNTS(0, 0);
   1590     }
   1591 
   1592 #undef ADD_OPAQUE_COUNTS
   1593 #undef ADD_TRANSL_COUNTS
   1594 
   1595     /* Now that we have it encoded, release the original pixels */
   1596     if((surface->flags & SDL_PREALLOC) != SDL_PREALLOC
   1597        && (surface->flags & SDL_HWSURFACE) != SDL_HWSURFACE) {
   1598 	SDL_free( surface->pixels );
   1599 	surface->pixels = NULL;
   1600     }
   1601 
   1602     /* realloc the buffer to release unused memory */
   1603     {
   1604 	Uint8 *p = SDL_realloc(rlebuf, dst - rlebuf);
   1605 	if(!p)
   1606 	    p = rlebuf;
   1607 	surface->map->sw_data->aux_data = p;
   1608     }
   1609 
   1610     return 0;
   1611 }
   1612 
   1613 static Uint32 getpix_8(Uint8 *srcbuf)
   1614 {
   1615     return *srcbuf;
   1616 }
   1617 
   1618 static Uint32 getpix_16(Uint8 *srcbuf)
   1619 {
   1620     return *(Uint16 *)srcbuf;
   1621 }
   1622 
   1623 static Uint32 getpix_24(Uint8 *srcbuf)
   1624 {
   1625 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
   1626     return srcbuf[0] + (srcbuf[1] << 8) + (srcbuf[2] << 16);
   1627 #else
   1628     return (srcbuf[0] << 16) + (srcbuf[1] << 8) + srcbuf[2];
   1629 #endif
   1630 }
   1631 
   1632 static Uint32 getpix_32(Uint8 *srcbuf)
   1633 {
   1634     return *(Uint32 *)srcbuf;
   1635 }
   1636 
   1637 typedef Uint32 (*getpix_func)(Uint8 *);
   1638 
   1639 static getpix_func getpixes[4] = {
   1640     getpix_8, getpix_16, getpix_24, getpix_32
   1641 };
   1642 
   1643 static int RLEColorkeySurface(SDL_Surface *surface)
   1644 {
   1645         Uint8 *rlebuf, *dst;
   1646 	int maxn;
   1647 	int y;
   1648 	Uint8 *srcbuf, *lastline;
   1649 	int maxsize = 0;
   1650 	int bpp = surface->format->BytesPerPixel;
   1651 	getpix_func getpix;
   1652 	Uint32 ckey, rgbmask;
   1653 	int w, h;
   1654 
   1655 	/* calculate the worst case size for the compressed surface */
   1656 	switch(bpp) {
   1657 	case 1:
   1658 	    /* worst case is alternating opaque and transparent pixels,
   1659 	       starting with an opaque pixel */
   1660 	    maxsize = surface->h * 3 * (surface->w / 2 + 1) + 2;
   1661 	    break;
   1662 	case 2:
   1663 	case 3:
   1664 	    /* worst case is solid runs, at most 255 pixels wide */
   1665 	    maxsize = surface->h * (2 * (surface->w / 255 + 1)
   1666 				    + surface->w * bpp) + 2;
   1667 	    break;
   1668 	case 4:
   1669 	    /* worst case is solid runs, at most 65535 pixels wide */
   1670 	    maxsize = surface->h * (4 * (surface->w / 65535 + 1)
   1671 				    + surface->w * 4) + 4;
   1672 	    break;
   1673 	}
   1674 
   1675 	rlebuf = (Uint8 *)SDL_malloc(maxsize);
   1676 	if ( rlebuf == NULL ) {
   1677 		SDL_OutOfMemory();
   1678 		return(-1);
   1679 	}
   1680 
   1681 	/* Set up the conversion */
   1682 	srcbuf = (Uint8 *)surface->pixels;
   1683 	maxn = bpp == 4 ? 65535 : 255;
   1684 	dst = rlebuf;
   1685 	rgbmask = ~surface->format->Amask;
   1686 	ckey = surface->format->colorkey & rgbmask;
   1687 	lastline = dst;
   1688 	getpix = getpixes[bpp - 1];
   1689 	w = surface->w;
   1690 	h = surface->h;
   1691 
   1692 #define ADD_COUNTS(n, m)			\
   1693 	if(bpp == 4) {				\
   1694 	    ((Uint16 *)dst)[0] = n;		\
   1695 	    ((Uint16 *)dst)[1] = m;		\
   1696 	    dst += 4;				\
   1697 	} else {				\
   1698 	    dst[0] = n;				\
   1699 	    dst[1] = m;				\
   1700 	    dst += 2;				\
   1701 	}
   1702 
   1703 	for(y = 0; y < h; y++) {
   1704 	    int x = 0;
   1705 	    int blankline = 0;
   1706 	    do {
   1707 		int run, skip, len;
   1708 		int runstart;
   1709 		int skipstart = x;
   1710 
   1711 		/* find run of transparent, then opaque pixels */
   1712 		while(x < w && (getpix(srcbuf + x * bpp) & rgbmask) == ckey)
   1713 		    x++;
   1714 		runstart = x;
   1715 		while(x < w && (getpix(srcbuf + x * bpp) & rgbmask) != ckey)
   1716 		    x++;
   1717 		skip = runstart - skipstart;
   1718 		if(skip == w)
   1719 		    blankline = 1;
   1720 		run = x - runstart;
   1721 
   1722 		/* encode segment */
   1723 		while(skip > maxn) {
   1724 		    ADD_COUNTS(maxn, 0);
   1725 		    skip -= maxn;
   1726 		}
   1727 		len = MIN(run, maxn);
   1728 		ADD_COUNTS(skip, len);
   1729 		SDL_memcpy(dst, srcbuf + runstart * bpp, len * bpp);
   1730 		dst += len * bpp;
   1731 		run -= len;
   1732 		runstart += len;
   1733 		while(run) {
   1734 		    len = MIN(run, maxn);
   1735 		    ADD_COUNTS(0, len);
   1736 		    SDL_memcpy(dst, srcbuf + runstart * bpp, len * bpp);
   1737 		    dst += len * bpp;
   1738 		    runstart += len;
   1739 		    run -= len;
   1740 		}
   1741 		if(!blankline)
   1742 		    lastline = dst;
   1743 	    } while(x < w);
   1744 
   1745 	    srcbuf += surface->pitch;
   1746 	}
   1747 	dst = lastline;		/* back up bast trailing blank lines */
   1748 	ADD_COUNTS(0, 0);
   1749 
   1750 #undef ADD_COUNTS
   1751 
   1752 	/* Now that we have it encoded, release the original pixels */
   1753 	if((surface->flags & SDL_PREALLOC) != SDL_PREALLOC
   1754 	   && (surface->flags & SDL_HWSURFACE) != SDL_HWSURFACE) {
   1755 	    SDL_free( surface->pixels );
   1756 	    surface->pixels = NULL;
   1757 	}
   1758 
   1759 	/* realloc the buffer to release unused memory */
   1760 	{
   1761 	    /* If realloc returns NULL, the original block is left intact */
   1762 	    Uint8 *p = SDL_realloc(rlebuf, dst - rlebuf);
   1763 	    if(!p)
   1764 		p = rlebuf;
   1765 	    surface->map->sw_data->aux_data = p;
   1766 	}
   1767 
   1768 	return(0);
   1769 }
   1770 
   1771 int SDL_RLESurface(SDL_Surface *surface)
   1772 {
   1773 	int retcode;
   1774 
   1775 	/* Clear any previous RLE conversion */
   1776 	if ( (surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
   1777 		SDL_UnRLESurface(surface, 1);
   1778 	}
   1779 
   1780 	/* We don't support RLE encoding of bitmaps */
   1781 	if ( surface->format->BitsPerPixel < 8 ) {
   1782 		return(-1);
   1783 	}
   1784 
   1785 	/* Lock the surface if it's in hardware */
   1786 	if ( SDL_MUSTLOCK(surface) ) {
   1787 		if ( SDL_LockSurface(surface) < 0 ) {
   1788 			return(-1);
   1789 		}
   1790 	}
   1791 
   1792 	/* Encode */
   1793 	if((surface->flags & SDL_SRCCOLORKEY) == SDL_SRCCOLORKEY) {
   1794 	    retcode = RLEColorkeySurface(surface);
   1795 	} else {
   1796 	    if((surface->flags & SDL_SRCALPHA) == SDL_SRCALPHA
   1797 	       && surface->format->Amask != 0)
   1798 		retcode = RLEAlphaSurface(surface);
   1799 	    else
   1800 		retcode = -1;	/* no RLE for per-surface alpha sans ckey */
   1801 	}
   1802 
   1803 	/* Unlock the surface if it's in hardware */
   1804 	if ( SDL_MUSTLOCK(surface) ) {
   1805 		SDL_UnlockSurface(surface);
   1806 	}
   1807 
   1808 	if(retcode < 0)
   1809 	    return -1;
   1810 
   1811 	/* The surface is now accelerated */
   1812 	surface->flags |= SDL_RLEACCEL;
   1813 
   1814 	return(0);
   1815 }
   1816 
   1817 /*
   1818  * Un-RLE a surface with pixel alpha
   1819  * This may not give back exactly the image before RLE-encoding; all
   1820  * completely transparent pixels will be lost, and colour and alpha depth
   1821  * may have been reduced (when encoding for 16bpp targets).
   1822  */
   1823 static SDL_bool UnRLEAlpha(SDL_Surface *surface)
   1824 {
   1825     Uint8 *srcbuf;
   1826     Uint32 *dst;
   1827     SDL_PixelFormat *sf = surface->format;
   1828     RLEDestFormat *df = surface->map->sw_data->aux_data;
   1829     int (*uncopy_opaque)(Uint32 *, void *, int,
   1830 			 RLEDestFormat *, SDL_PixelFormat *);
   1831     int (*uncopy_transl)(Uint32 *, void *, int,
   1832 			 RLEDestFormat *, SDL_PixelFormat *);
   1833     int w = surface->w;
   1834     int bpp = df->BytesPerPixel;
   1835 
   1836     if(bpp == 2) {
   1837 	uncopy_opaque = uncopy_opaque_16;
   1838 	uncopy_transl = uncopy_transl_16;
   1839     } else {
   1840 	uncopy_opaque = uncopy_transl = uncopy_32;
   1841     }
   1842 
   1843     surface->pixels = SDL_malloc(surface->h * surface->pitch);
   1844     if ( !surface->pixels ) {
   1845         return(SDL_FALSE);
   1846     }
   1847     /* fill background with transparent pixels */
   1848     SDL_memset(surface->pixels, 0, surface->h * surface->pitch);
   1849 
   1850     dst = surface->pixels;
   1851     srcbuf = (Uint8 *)(df + 1);
   1852     for(;;) {
   1853 	/* copy opaque pixels */
   1854 	int ofs = 0;
   1855 	do {
   1856 	    unsigned run;
   1857 	    if(bpp == 2) {
   1858 		ofs += srcbuf[0];
   1859 		run = srcbuf[1];
   1860 		srcbuf += 2;
   1861 	    } else {
   1862 		ofs += ((Uint16 *)srcbuf)[0];
   1863 		run = ((Uint16 *)srcbuf)[1];
   1864 		srcbuf += 4;
   1865 	    }
   1866 	    if(run) {
   1867 		srcbuf += uncopy_opaque(dst + ofs, srcbuf, run, df, sf);
   1868 		ofs += run;
   1869 	    } else if(!ofs)
   1870 		return(SDL_TRUE);
   1871 	} while(ofs < w);
   1872 
   1873 	/* skip padding if needed */
   1874 	if(bpp == 2)
   1875 	    srcbuf += (uintptr_t)srcbuf & 2;
   1876 
   1877 	/* copy translucent pixels */
   1878 	ofs = 0;
   1879 	do {
   1880 	    unsigned run;
   1881 	    ofs += ((Uint16 *)srcbuf)[0];
   1882 	    run = ((Uint16 *)srcbuf)[1];
   1883 	    srcbuf += 4;
   1884 	    if(run) {
   1885 		srcbuf += uncopy_transl(dst + ofs, srcbuf, run, df, sf);
   1886 		ofs += run;
   1887 	    }
   1888 	} while(ofs < w);
   1889 	dst += surface->pitch >> 2;
   1890     }
   1891     /* Make the compiler happy */
   1892     return(SDL_TRUE);
   1893 }
   1894 
   1895 void SDL_UnRLESurface(SDL_Surface *surface, int recode)
   1896 {
   1897     if ( (surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
   1898 	surface->flags &= ~SDL_RLEACCEL;
   1899 
   1900 	if(recode && (surface->flags & SDL_PREALLOC) != SDL_PREALLOC
   1901 	   && (surface->flags & SDL_HWSURFACE) != SDL_HWSURFACE) {
   1902 	    if((surface->flags & SDL_SRCCOLORKEY) == SDL_SRCCOLORKEY) {
   1903 		SDL_Rect full;
   1904 		unsigned alpha_flag;
   1905 
   1906 		/* re-create the original surface */
   1907 		surface->pixels = SDL_malloc(surface->h * surface->pitch);
   1908 		if ( !surface->pixels ) {
   1909 			/* Oh crap... */
   1910 			surface->flags |= SDL_RLEACCEL;
   1911 			return;
   1912 		}
   1913 
   1914 		/* fill it with the background colour */
   1915 		SDL_FillRect(surface, NULL, surface->format->colorkey);
   1916 
   1917 		/* now render the encoded surface */
   1918 		full.x = full.y = 0;
   1919 		full.w = surface->w;
   1920 		full.h = surface->h;
   1921 		alpha_flag = surface->flags & SDL_SRCALPHA;
   1922 		surface->flags &= ~SDL_SRCALPHA; /* opaque blit */
   1923 		SDL_RLEBlit(surface, &full, surface, &full);
   1924 		surface->flags |= alpha_flag;
   1925 	    } else {
   1926 		if ( !UnRLEAlpha(surface) ) {
   1927 		    /* Oh crap... */
   1928 		    surface->flags |= SDL_RLEACCEL;
   1929 		    return;
   1930 		}
   1931 	    }
   1932 	}
   1933 
   1934 	if ( surface->map && surface->map->sw_data->aux_data ) {
   1935 	    SDL_free(surface->map->sw_data->aux_data);
   1936 	    surface->map->sw_data->aux_data = NULL;
   1937 	}
   1938     }
   1939 }
   1940 
   1941 
   1942