Commit 830979c5555274daccfe9575bef492a030f5dffc

Sylvain Becker 2019-08-31T22:52:15

LoadBMP: use code from SDL_image which allows loading compressed BMP files

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
diff --git a/src/video/SDL_bmp.c b/src/video/SDL_bmp.c
index a06b0c9..a10ea2c 100644
--- a/src/video/SDL_bmp.c
+++ b/src/video/SDL_bmp.c
@@ -54,6 +54,92 @@
 #define LCS_WINDOWS_COLOR_SPACE    0x57696E20
 #endif
 
+static int readRlePixels(SDL_Surface * surface, SDL_RWops * src, int isRle8)
+{
+    /*
+    | Sets the surface pixels from src.  A bmp image is upside down.
+    */
+    int pitch = surface->pitch;
+    int height = surface->h;
+    Uint8 *start = (Uint8 *)surface->pixels;
+    Uint8 *end = start + (height*pitch);
+    Uint8 *bits = end-pitch, *spot;
+    int ofs = 0;
+    Uint8 ch;
+    Uint8 needsPad;
+
+#define COPY_PIXEL(x)   spot = &bits[ofs++]; if(spot >= start && spot < end) *spot = (x)
+
+    for (;;) {
+        if ( !SDL_RWread(src, &ch, 1, 1) ) return 1;
+        /*
+        | encoded mode starts with a run length, and then a byte
+        | with two colour indexes to alternate between for the run
+        */
+        if ( ch ) {
+            Uint8 pixel;
+            if ( !SDL_RWread(src, &pixel, 1, 1) ) return 1;
+            if ( isRle8 ) {                 /* 256-color bitmap, compressed */
+                do {
+                    COPY_PIXEL(pixel);
+                } while (--ch);
+            } else {                         /* 16-color bitmap, compressed */
+                Uint8 pixel0 = pixel >> 4;
+                Uint8 pixel1 = pixel & 0x0F;
+                for (;;) {
+                    COPY_PIXEL(pixel0); /* even count, high nibble */
+                    if (!--ch) break;
+                    COPY_PIXEL(pixel1); /* odd count, low nibble */
+                    if (!--ch) break;
+                }
+            }
+        } else {
+            /*
+            | A leading zero is an escape; it may signal the end of the bitmap,
+            | a cursor move, or some absolute data.
+            | zero tag may be absolute mode or an escape
+            */
+            if ( !SDL_RWread(src, &ch, 1, 1) ) return 1;
+            switch (ch) {
+            case 0:                         /* end of line */
+                ofs = 0;
+                bits -= pitch;               /* go to previous */
+                break;
+            case 1:                         /* end of bitmap */
+                return 0;                    /* success! */
+            case 2:                         /* delta */
+                if ( !SDL_RWread(src, &ch, 1, 1) ) return 1;
+                ofs += ch;
+                if ( !SDL_RWread(src, &ch, 1, 1) ) return 1;
+                bits -= (ch * pitch);
+                break;
+            default:                        /* no compression */
+                if (isRle8) {
+                    needsPad = ( ch & 1 );
+                    do {
+                        Uint8 pixel;
+                        if ( !SDL_RWread(src, &pixel, 1, 1) ) return 1;
+                        COPY_PIXEL(pixel);
+                    } while (--ch);
+                } else {
+                    needsPad = ( ((ch+1)>>1) & 1 ); /* (ch+1)>>1: bytes size */
+                    for (;;) {
+                        Uint8 pixel;
+                        if ( !SDL_RWread(src, &pixel, 1, 1) ) return 1;
+                        COPY_PIXEL(pixel >> 4);
+                        if (!--ch) break;
+                        COPY_PIXEL(pixel & 0x0F);
+                        if (!--ch) break;
+                    }
+                }
+                /* pad at even boundary */
+                if ( needsPad && !SDL_RWread(src, &ch, 1, 1) ) return 1;
+                break;
+            }
+        }
+    }
+}
+
 static void CorrectAlphaChannel(SDL_Surface *surface)
 {
     /* Check to see if there is any alpha channel data */
@@ -87,7 +173,7 @@ SDL_Surface *
 SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
 {
     SDL_bool was_error;
-    Sint64 fp_offset = 0;
+    Sint64 fp_offset;
     int bmpPitch;
     int i, pad;
     SDL_Surface *surface;
@@ -105,32 +191,29 @@ SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
     SDL_bool correctAlpha = SDL_FALSE;
 
     /* The Win32 BMP file header (14 bytes) */
-    char magic[2];
-    /* Uint32 bfSize = 0; */
-    /* Uint16 bfReserved1 = 0; */
-    /* Uint16 bfReserved2 = 0; */
-    Uint32 bfOffBits = 0;
+    char   magic[2];
+    Uint32 bfSize;
+    Uint16 bfReserved1;
+    Uint16 bfReserved2;
+    Uint32 bfOffBits;
 
     /* The Win32 BITMAPINFOHEADER struct (40 bytes) */
-    Uint32 biSize = 0;
-    Sint32 biWidth = 0;
+    Uint32 biSize;
+    Sint32 biWidth;
     Sint32 biHeight = 0;
-    /* Uint16 biPlanes = 0; */
-    Uint16 biBitCount = 0;
-    Uint32 biCompression = 0;
-    /* Uint32 biSizeImage = 0; */
-    /* Sint32 biXPelsPerMeter = 0; */
-    /* Sint32 biYPelsPerMeter = 0; */
-    Uint32 biClrUsed = 0;
-    /* Uint32 biClrImportant = 0; */
-
-    (void) haveRGBMasks;
-    (void) haveAlphaMask;
+    Uint16 biPlanes;
+    Uint16 biBitCount;
+    Uint32 biCompression;
+    Uint32 biSizeImage;
+    Sint32 biXPelsPerMeter;
+    Sint32 biYPelsPerMeter;
+    Uint32 biClrUsed;
+    Uint32 biClrImportant;
 
     /* Make sure we are passed a valid data source */
     surface = NULL;
     was_error = SDL_FALSE;
-    if (src == NULL) {
+    if ( src == NULL ) {
         was_error = SDL_TRUE;
         goto done;
     }
@@ -138,52 +221,49 @@ SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
     /* Read in the BMP file header */
     fp_offset = SDL_RWtell(src);
     SDL_ClearError();
-    if (SDL_RWread(src, magic, 1, 2) != 2) {
+    if ( SDL_RWread(src, magic, 1, 2) != 2 ) {
         SDL_Error(SDL_EFREAD);
         was_error = SDL_TRUE;
         goto done;
     }
-    if (SDL_strncmp(magic, "BM", 2) != 0) {
+    if ( SDL_strncmp(magic, "BM", 2) != 0 ) {
         SDL_SetError("File is not a Windows BMP file");
         was_error = SDL_TRUE;
         goto done;
     }
-    /* bfSize = */ SDL_ReadLE32(src);
-    /* bfReserved1 = */ SDL_ReadLE16(src);
-    /* bfReserved2 = */ SDL_ReadLE16(src);
-    bfOffBits = SDL_ReadLE32(src);
+    bfSize      = SDL_ReadLE32(src);
+    bfReserved1 = SDL_ReadLE16(src);
+    bfReserved2 = SDL_ReadLE16(src);
+    bfOffBits   = SDL_ReadLE32(src);
 
     /* Read the Win32 BITMAPINFOHEADER */
-    biSize = SDL_ReadLE32(src);
-    if (biSize == 12) {   /* really old BITMAPCOREHEADER */
-        biWidth = (Uint32) SDL_ReadLE16(src);
-        biHeight = (Uint32) SDL_ReadLE16(src);
-        /* biPlanes = */ SDL_ReadLE16(src);
-        biBitCount = SDL_ReadLE16(src);
-        biCompression = BI_RGB;
+    biSize      = SDL_ReadLE32(src);
+    if ( biSize == 12 ) {   /* really old BITMAPCOREHEADER */
+        biWidth     = (Uint32)SDL_ReadLE16(src);
+        biHeight    = (Uint32)SDL_ReadLE16(src);
+        biPlanes    = SDL_ReadLE16(src);
+        biBitCount  = SDL_ReadLE16(src);
+        biCompression   = BI_RGB;
+        biSizeImage = 0;
+        biXPelsPerMeter = 0;
+        biYPelsPerMeter = 0;
+        biClrUsed   = 0;
+        biClrImportant  = 0;
     } else if (biSize >= 40) {  /* some version of BITMAPINFOHEADER */
         Uint32 headerSize;
-        biWidth = SDL_ReadLE32(src);
-        biHeight = SDL_ReadLE32(src);
-        /* biPlanes = */ SDL_ReadLE16(src);
-        biBitCount = SDL_ReadLE16(src);
-        biCompression = SDL_ReadLE32(src);
-        /* biSizeImage = */ SDL_ReadLE32(src);
-        /* biXPelsPerMeter = */ SDL_ReadLE32(src);
-        /* biYPelsPerMeter = */ SDL_ReadLE32(src);
-        biClrUsed = SDL_ReadLE32(src);
-        /* biClrImportant = */ SDL_ReadLE32(src);
+        biWidth     = SDL_ReadLE32(src);
+        biHeight    = SDL_ReadLE32(src);
+        biPlanes    = SDL_ReadLE16(src);
+        biBitCount  = SDL_ReadLE16(src);
+        biCompression   = SDL_ReadLE32(src);
+        biSizeImage = SDL_ReadLE32(src);
+        biXPelsPerMeter = SDL_ReadLE32(src);
+        biYPelsPerMeter = SDL_ReadLE32(src);
+        biClrUsed   = SDL_ReadLE32(src);
+        biClrImportant  = SDL_ReadLE32(src);
 
         /* 64 == BITMAPCOREHEADER2, an incompatible OS/2 2.x extension. Skip this stuff for now. */
-        if (biSize == 64) {
-            /* ignore these extra fields. */
-            if (biCompression == BI_BITFIELDS) {
-                /* this value is actually huffman compression in this variant. */
-                SDL_SetError("Compressed BMP files not supported");
-                was_error = SDL_TRUE;
-                goto done;
-            }
-        } else {
+        if (biSize != 64) {
             /* This is complicated. If compression is BI_BITFIELDS, then
                we have 3 DWORDS that specify the RGB masks. This is either
                stored here in an BITMAPV2INFOHEADER (which only differs in
@@ -246,117 +326,102 @@ SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
 
     /* Expand 1 and 4 bit bitmaps to 8 bits per pixel */
     switch (biBitCount) {
-    case 1:
-    case 4:
-        ExpandBMP = biBitCount;
-        biBitCount = 8;
-        break;
-    case 2:
-    case 3:
-    case 5:
-    case 6:
-    case 7:
-		SDL_SetError("%d-bpp BMP images are not supported", biBitCount);
-        was_error = SDL_TRUE;
-        goto done;
-    default:
-        ExpandBMP = 0;
-        break;
+        case 1:
+        case 4:
+            ExpandBMP = biBitCount;
+            biBitCount = 8;
+            break;
+        case 2:
+        case 3:
+        case 5:
+        case 6:
+        case 7:
+            SDL_SetError("%d-bpp BMP images are not supported", biBitCount);
+            was_error = SDL_TRUE;
+            goto done;
+        default:
+            ExpandBMP = 0;
+            break;
     }
 
-    /* We don't support any BMP compression right now */
+    /* RLE4 and RLE8 BMP compression is supported */
     switch (biCompression) {
-    case BI_RGB:
-        /* If there are no masks, use the defaults */
-        SDL_assert(!haveRGBMasks);
-        SDL_assert(!haveAlphaMask);
-        /* Default values for the BMP format */
-        switch (biBitCount) {
-        case 15:
-        case 16:
-            Rmask = 0x7C00;
-            Gmask = 0x03E0;
-            Bmask = 0x001F;
-            break;
-        case 24:
+        case BI_RGB:
+            /* If there are no masks, use the defaults */
+            SDL_assert(!haveRGBMasks);
+            SDL_assert(!haveAlphaMask);
+            /* Default values for the BMP format */
+            switch (biBitCount) {
+            case 15:
+            case 16:
+                Rmask = 0x7C00;
+                Gmask = 0x03E0;
+                Bmask = 0x001F;
+                break;
+            case 24:
 #if SDL_BYTEORDER == SDL_BIG_ENDIAN
-            Rmask = 0x000000FF;
-            Gmask = 0x0000FF00;
-            Bmask = 0x00FF0000;
+                Rmask = 0x000000FF;
+                Gmask = 0x0000FF00;
+                Bmask = 0x00FF0000;
 #else
-            Rmask = 0x00FF0000;
-            Gmask = 0x0000FF00;
-            Bmask = 0x000000FF;
+                Rmask = 0x00FF0000;
+                Gmask = 0x0000FF00;
+                Bmask = 0x000000FF;
 #endif
+                break;
+            case 32:
+                /* We don't know if this has alpha channel or not */
+                correctAlpha = SDL_TRUE;
+                Amask = 0xFF000000;
+                Rmask = 0x00FF0000;
+                Gmask = 0x0000FF00;
+                Bmask = 0x000000FF;
+                break;
+            default:
+                break;
+            }
             break;
-        case 32:
-            /* We don't know if this has alpha channel or not */
-            correctAlpha = SDL_TRUE;
-            Amask = 0xFF000000;
-            Rmask = 0x00FF0000;
-            Gmask = 0x0000FF00;
-            Bmask = 0x000000FF;
-            break;
-        default:
-            break;
-        }
-        break;
 
-    case BI_BITFIELDS:
-        break;  /* we handled this in the info header. */
+        case BI_BITFIELDS:
+            break;  /* we handled this in the info header. */
 
-    default:
-        SDL_SetError("Compressed BMP files not supported");
-        was_error = SDL_TRUE;
-        goto done;
+        default:
+            break;
     }
 
     /* Create a compatible surface, note that the colors are RGB ordered */
-    surface =
-        SDL_CreateRGBSurface(0, biWidth, biHeight, biBitCount, Rmask, Gmask,
-                             Bmask, Amask);
-    if (surface == NULL) {
+    surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
+            biWidth, biHeight, biBitCount, Rmask, Gmask, Bmask, Amask);
+    if ( surface == NULL ) {
         was_error = SDL_TRUE;
         goto done;
     }
 
     /* Load the palette, if any */
     palette = (surface->format)->palette;
-    if (palette) {
-        SDL_assert(biBitCount <= 8);
-        if (biClrUsed == 0) {
-            biClrUsed = 1 << biBitCount;
-		} else if (biClrUsed > (Uint32)(1 << biBitCount)) {
-			SDL_SetError("BMP file has an invalid number of colors");
-			was_error = SDL_TRUE;
-			goto done;
-        }
-        if ((int) biClrUsed > palette->ncolors) {
-            SDL_Color *colors;
-            int ncolors = biClrUsed;
-            colors =
-                (SDL_Color *) SDL_realloc(palette->colors,
-                                          ncolors *
-                                          sizeof(*palette->colors));
-            if (!colors) {
-                SDL_OutOfMemory();
-                was_error = SDL_TRUE;
-                goto done;
-            }
-            palette->ncolors = ncolors;
-            palette->colors = colors;
-        } else if ((int) biClrUsed < palette->ncolors) {
-            palette->ncolors = biClrUsed;
+    if ( palette ) {
+        if ( SDL_RWseek(src, fp_offset+14+biSize, RW_SEEK_SET) < 0 ) {
+            SDL_Error(SDL_EFSEEK);
+            was_error = SDL_TRUE;
+            goto done;
         }
-        if (biSize == 12) {
-            for (i = 0; i < (int) biClrUsed; ++i) {
+
+        /*
+        | guich: always use 1<<bpp b/c some bitmaps can bring wrong information
+        | for colorsUsed
+        */
+        /* if ( biClrUsed == 0 ) {  */
+        biClrUsed = 1 << biBitCount;
+        /* } */
+        if ( biSize == 12 ) {
+            for ( i = 0; i < (int)biClrUsed; ++i ) {
                 SDL_RWread(src, &palette->colors[i].b, 1, 1);
                 SDL_RWread(src, &palette->colors[i].g, 1, 1);
                 SDL_RWread(src, &palette->colors[i].r, 1, 1);
                 palette->colors[i].a = SDL_ALPHA_OPAQUE;
             }
         } else {
-            for (i = 0; i < (int) biClrUsed; ++i) {
+            for ( i = 0; i < (int)biClrUsed; ++i ) {
                 SDL_RWread(src, &palette->colors[i].b, 1, 1);
                 SDL_RWread(src, &palette->colors[i].g, 1, 1);
                 SDL_RWread(src, &palette->colors[i].r, 1, 1);
@@ -369,104 +434,111 @@ SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
                 palette->colors[i].a = SDL_ALPHA_OPAQUE;
             }
         }
+        palette->ncolors = biClrUsed;
     }
 
     /* Read the surface pixels.  Note that the bmp image is upside down */
-    if (SDL_RWseek(src, fp_offset + bfOffBits, RW_SEEK_SET) < 0) {
+    if ( SDL_RWseek(src, fp_offset+bfOffBits, RW_SEEK_SET) < 0 ) {
         SDL_Error(SDL_EFSEEK);
         was_error = SDL_TRUE;
         goto done;
     }
+    if ((biCompression == BI_RLE4) || (biCompression == BI_RLE8)) {
+        was_error = (SDL_bool)readRlePixels(surface, src, biCompression == BI_RLE8);
+        if (was_error) SDL_SetError("Error reading from BMP");
+        goto done;
+    }
     top = (Uint8 *)surface->pixels;
     end = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
     switch (ExpandBMP) {
-    case 1:
-        bmpPitch = (biWidth + 7) >> 3;
-        pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
-        break;
-    case 4:
-        bmpPitch = (biWidth + 1) >> 1;
-        pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
-        break;
-    default:
-        pad = ((surface->pitch % 4) ? (4 - (surface->pitch % 4)) : 0);
-        break;
+        case 1:
+            bmpPitch = (biWidth + 7) >> 3;
+            pad  = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0);
+            break;
+        case 4:
+            bmpPitch = (biWidth + 1) >> 1;
+            pad  = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0);
+            break;
+        default:
+            pad  = ((surface->pitch%4) ?
+                    (4-(surface->pitch%4)) : 0);
+            break;
     }
-    if (topDown) {
+    if ( topDown ) {
         bits = top;
     } else {
         bits = end - surface->pitch;
     }
-    while (bits >= top && bits < end) {
+    while ( bits >= top && bits < end ) {
         switch (ExpandBMP) {
-        case 1:
-        case 4:{
+            case 1:
+            case 4: {
                 Uint8 pixel = 0;
-                int shift = (8 - ExpandBMP);
-                for (i = 0; i < surface->w; ++i) {
-                    if (i % (8 / ExpandBMP) == 0) {
-                        if (!SDL_RWread(src, &pixel, 1, 1)) {
+                int   shift = (8-ExpandBMP);
+                for ( i=0; i<surface->w; ++i ) {
+                    if ( i%(8/ExpandBMP) == 0 ) {
+                        if ( !SDL_RWread(src, &pixel, 1, 1) ) {
                             SDL_SetError("Error reading from BMP");
                             was_error = SDL_TRUE;
                             goto done;
                         }
                     }
                     bits[i] = (pixel >> shift);
-					if (bits[i] >= biClrUsed) {
-						SDL_SetError("A BMP image contains a pixel with a color out of the palette");
-						was_error = SDL_TRUE;
-						goto done;
-					}
+                    if (bits[i] >= biClrUsed) {
+                        SDL_SetError("A BMP image contains a pixel with a color out of the palette");
+                        was_error = SDL_TRUE;
+                        goto done;
+                    }
                     pixel <<= ExpandBMP;
                 }
             }
             break;
 
-        default:
-            if (SDL_RWread(src, bits, 1, surface->pitch) != surface->pitch) {
-                SDL_Error(SDL_EFREAD);
-                was_error = SDL_TRUE;
-                goto done;
-            }
-			if (biBitCount == 8 && palette && biClrUsed < (Uint32)(1 << biBitCount)) {
-				for (i = 0; i < surface->w; ++i) {
-					if (bits[i] >= biClrUsed) {
-						SDL_SetError("A BMP image contains a pixel with a color out of the palette");
-						was_error = SDL_TRUE;
-						goto done;
-					}
-				}
-			}
-#if SDL_BYTEORDER == SDL_BIG_ENDIAN
-            /* Byte-swap the pixels if needed. Note that the 24bpp
-               case has already been taken care of above. */
-            switch (biBitCount) {
-            case 15:
-            case 16:{
-                    Uint16 *pix = (Uint16 *) bits;
-                    for (i = 0; i < surface->w; i++)
-                        pix[i] = SDL_Swap16(pix[i]);
-                    break;
+            default:
+                if ( SDL_RWread(src, bits, 1, surface->pitch) != surface->pitch ) {
+                    SDL_Error(SDL_EFREAD);
+                    was_error = SDL_TRUE;
+                    goto done;
+                }
+                if (biBitCount == 8 && palette && biClrUsed < (1 << biBitCount)) {
+                    for (i = 0; i < surface->w; ++i) {
+                        if (bits[i] >= biClrUsed) {
+                            SDL_SetError("A BMP image contains a pixel with a color out of the palette");
+                            was_error = SDL_TRUE;
+                            goto done;
+                        }
+                    }
                 }
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+                /* Byte-swap the pixels if needed. Note that the 24bpp
+                   case has already been taken care of above. */
+                switch(biBitCount) {
+                    case 15:
+                    case 16: {
+                        Uint16 *pix = (Uint16 *)bits;
+                        for(i = 0; i < surface->w; i++)
+                            pix[i] = SDL_Swap16(pix[i]);
+                        break;
+                    }
 
-            case 32:{
-                    Uint32 *pix = (Uint32 *) bits;
-                    for (i = 0; i < surface->w; i++)
-                        pix[i] = SDL_Swap32(pix[i]);
-                    break;
+                    case 32: {
+                        Uint32 *pix = (Uint32 *)bits;
+                        for(i = 0; i < surface->w; i++)
+                            pix[i] = SDL_Swap32(pix[i]);
+                        break;
+                    }
                 }
-            }
 #endif
-            break;
+                break;
         }
         /* Skip padding bytes, ugh */
-        if (pad) {
+        if ( pad ) {
             Uint8 padbyte;
-            for (i = 0; i < pad; ++i) {
+            for ( i=0; i<pad; ++i ) {
                 SDL_RWread(src, &padbyte, 1, 1);
             }
         }
-        if (topDown) {
+        if ( topDown ) {
             bits += surface->pitch;
         } else {
             bits -= surface->pitch;
@@ -475,18 +547,20 @@ SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
     if (correctAlpha) {
         CorrectAlphaChannel(surface);
     }
-  done:
-    if (was_error) {
-        if (src) {
+done:
+    if ( was_error ) {
+        if ( src ) {
             SDL_RWseek(src, fp_offset, RW_SEEK_SET);
         }
-        SDL_FreeSurface(surface);
+        if ( surface ) {
+            SDL_FreeSurface(surface);
+        }
         surface = NULL;
     }
-    if (freesrc && src) {
+    if ( freesrc && src ) {
         SDL_RWclose(src);
     }
-    return (surface);
+    return(surface);
 }
 
 int