src/bmp.cpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /** @file bmp.cpp Read and write support for bmps. */
  11
  12 #include "stdafx.h"
  13 #include "bmp.h"
  14 #include "core/bitmath_func.hpp"
  15 #include "core/alloc_func.hpp"
  16 #include "core/mem_func.hpp"
  17
  18 #include "safeguards.h"
  19
  20 void BmpInitializeBuffer(BmpBuffer *buffer, FILE *file)
  21 {
  22         buffer->pos      = -1;
  23         buffer->file     = file;
  24         buffer->read     = 0;
  25         buffer->real_pos = ftell(file);
  26 }
  27
  28 static inline void AdvanceBuffer(BmpBuffer *buffer)
  29 {
  30         if (buffer->read < 0) return;
  31
  32         buffer->read = (int)fread(buffer->data, 1, BMP_BUFFER_SIZE, buffer->file);
  33         buffer->pos  = 0;
  34 }
  35
  36 static inline bool EndOfBuffer(BmpBuffer *buffer)
  37 {
  38         if (buffer->read < 0) return false;
  39
  40         if (buffer->pos == buffer->read || buffer->pos < 0) AdvanceBuffer(buffer);
  41         return buffer->pos == buffer->read;
  42 }
  43
  44 static inline byte ReadByte(BmpBuffer *buffer)
  45 {
  46         if (buffer->read < 0) return 0;
  47
  48         if (buffer->pos == buffer->read || buffer->pos < 0) AdvanceBuffer(buffer);
  49         buffer->real_pos++;
  50         return buffer->data[buffer->pos++];
  51 }
  52
  53 static inline uint16 ReadWord(BmpBuffer *buffer)
  54 {
  55         uint16 var = ReadByte(buffer);
  56         return var | (ReadByte(buffer) << 8);
  57 }
  58
  59 static inline uint32 ReadDword(BmpBuffer *buffer)
  60 {
  61         uint32 var = ReadWord(buffer);
  62         return var | (ReadWord(buffer) << 16);
  63 }
  64
  65 static inline void SkipBytes(BmpBuffer *buffer, int bytes)
  66 {
  67         int i;
  68         for (i = 0; i < bytes; i++) ReadByte(buffer);
  69 }
  70
  71 static inline void SetStreamOffset(BmpBuffer *buffer, int offset)
  72 {
  73         if (fseek(buffer->file, offset, SEEK_SET) < 0) {
  74                 buffer->read = -1;
  75         }
  76         buffer->pos = -1;
  77         buffer->real_pos = offset;
  78         AdvanceBuffer(buffer);
  79 }
  80
  81 /**
  82  * Reads a 1 bpp uncompressed bitmap
  83  * The bitmap is converted to a 8 bpp bitmap
  84  */
  85 static inline bool BmpRead1(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
  86 {
  87         uint x, y, i;
  88         byte pad = GB(4 - info->width / 8, 0, 2);
  89         byte *pixel_row;
  90         byte b;
  91         for (y = info->height; y > 0; y--) {
  92                 x = 0;
  93                 pixel_row = &data->bitmap[(y - 1) * info->width];
  94                 while (x < info->width) {
  95                         if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
  96                         b = ReadByte(buffer);
  97                         for (i = 8; i > 0; i--) {
  98                                 if (x < info->width) *pixel_row++ = GB(b, i - 1, 1);
  99                                 x++;
 100                         }
 101                 }
 102                 /* Padding for 32 bit align */
 103                 SkipBytes(buffer, pad);
 104         }
 105         return true;
 106 }
 107
 108 /**
 109  * Reads a 4 bpp uncompressed bitmap
 110  * The bitmap is converted to a 8 bpp bitmap
 111  */
 112 static inline bool BmpRead4(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 113 {
 114         uint x, y;
 115         byte pad = GB(4 - info->width / 2, 0, 2);
 116         byte *pixel_row;
 117         byte b;
 118         for (y = info->height; y > 0; y--) {
 119                 x = 0;
 120                 pixel_row = &data->bitmap[(y - 1) * info->width];
 121                 while (x < info->width) {
 122                         if (EndOfBuffer(buffer)) return false;  // the file is shorter than expected
 123                         b = ReadByte(buffer);
 124                         *pixel_row++ = GB(b, 4, 4);
 125                         x++;
 126                         if (x < info->width) {
 127                                 *pixel_row++ = GB(b, 0, 4);
 128                                 x++;
 129                         }
 130                 }
 131                 /* Padding for 32 bit align */
 132                 SkipBytes(buffer, pad);
 133         }
 134         return true;
 135 }
 136
 137 /**
 138  * Reads a 4-bit RLE compressed bitmap
 139  * The bitmap is converted to a 8 bpp bitmap
 140  */
 141 static inline bool BmpRead4Rle(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 142 {
 143         uint x = 0;
 144         uint y = info->height - 1;
 145         byte *pixel = &data->bitmap[y * info->width];
 146         while (y != 0 || x < info->width) {
 147                 if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
 148
 149                 byte n = ReadByte(buffer);
 150                 byte c = ReadByte(buffer);
 151                 if (n == 0) {
 152                         switch (c) {
 153                                 case 0: // end of line
 154                                         x = 0;
 155                                         if (y == 0) return false;
 156                                         pixel = &data->bitmap[--y * info->width];
 157                                         break;
 158
 159                                 case 1: // end of bitmap
 160                                         return true;
 161
 162                                 case 2: { // delta
 163                                         if (EndOfBuffer(buffer)) return false;
 164                                         byte dx = ReadByte(buffer);
 165                                         byte dy = ReadByte(buffer);
 166
 167                                         /* Check for over- and underflow. */
 168                                         if (x + dx >= info->width || x + dx < x || dy > y) return false;
 169
 170                                         x += dx;
 171                                         y -= dy;
 172                                         pixel = &data->bitmap[y * info->width + x];
 173                                         break;
 174                                 }
 175
 176                                 default: { // uncompressed
 177                                         uint i = 0;
 178                                         while (i++ < c) {
 179                                                 if (EndOfBuffer(buffer) || x >= info->width) return false;
 180                                                 byte b = ReadByte(buffer);
 181                                                 *pixel++ = GB(b, 4, 4);
 182                                                 x++;
 183                                                 if (i++ < c) {
 184                                                         if (x >= info->width) return false;
 185                                                         *pixel++ = GB(b, 0, 4);
 186                                                         x++;
 187                                                 }
 188                                         }
 189                                         /* Padding for 16 bit align */
 190                                         SkipBytes(buffer, ((c + 1) / 2) % 2);
 191                                         break;
 192                                 }
 193                         }
 194                 } else {
 195                         /* Apparently it is common to encounter BMPs where the count of
 196                          * pixels to be written is higher than the remaining line width.
 197                          * Ignore the superfluous pixels instead of reporting an error. */
 198                         uint i = 0;
 199                         while (x < info->width && i++ < n) {
 200                                 *pixel++ = GB(c, 4, 4);
 201                                 x++;
 202                                 if (x < info->width && i++ < n) {
 203                                         *pixel++ = GB(c, 0, 4);
 204                                         x++;
 205                                 }
 206                         }
 207                 }
 208         }
 209         return true;
 210 }
 211
 212 /**
 213  * Reads a 8 bpp bitmap
 214  */
 215 static inline bool BmpRead8(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 216 {
 217         uint i;
 218         uint y;
 219         byte pad = GB(4 - info->width, 0, 2);
 220         byte *pixel;
 221         for (y = info->height; y > 0; y--) {
 222                 if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
 223                 pixel = &data->bitmap[(y - 1) * info->width];
 224                 for (i = 0; i < info->width; i++) *pixel++ = ReadByte(buffer);
 225                 /* Padding for 32 bit align */
 226                 SkipBytes(buffer, pad);
 227         }
 228         return true;
 229 }
 230
 231 /**
 232  * Reads a 8-bit RLE compressed bpp bitmap
 233  */
 234 static inline bool BmpRead8Rle(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 235 {
 236         uint x = 0;
 237         uint y = info->height - 1;
 238         byte *pixel = &data->bitmap[y * info->width];
 239         while (y != 0 || x < info->width) {
 240                 if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
 241
 242                 byte n = ReadByte(buffer);
 243                 byte c = ReadByte(buffer);
 244                 if (n == 0) {
 245                         switch (c) {
 246                                 case 0: // end of line
 247                                         x = 0;
 248                                         if (y == 0) return false;
 249                                         pixel = &data->bitmap[--y * info->width];
 250                                         break;
 251
 252                                 case 1: // end of bitmap
 253                                         return true;
 254
 255                                 case 2: { // delta
 256                                         if (EndOfBuffer(buffer)) return false;
 257                                         byte dx = ReadByte(buffer);
 258                                         byte dy = ReadByte(buffer);
 259
 260                                         /* Check for over- and underflow. */
 261                                         if (x + dx >= info->width || x + dx < x || dy > y) return false;
 262
 263                                         x += dx;
 264                                         y -= dy;
 265                                         pixel = &data->bitmap[y * info->width + x];
 266                                         break;
 267                                 }
 268
 269                                 default: { // uncompressed
 270                                         for (uint i = 0; i < c; i++) {
 271                                                 if (EndOfBuffer(buffer) || x >= info->width) return false;
 272                                                 *pixel++ = ReadByte(buffer);
 273                                                 x++;
 274                                         }
 275                                         /* Padding for 16 bit align */
 276                                         SkipBytes(buffer, c % 2);
 277                                         break;
 278                                 }
 279                         }
 280                 } else {
 281                         /* Apparently it is common to encounter BMPs where the count of
 282                          * pixels to be written is higher than the remaining line width.
 283                          * Ignore the superfluous pixels instead of reporting an error. */
 284                         for (uint i = 0; x < info->width && i < n; i++) {
 285                                 *pixel++ = c;
 286                                 x++;
 287                         }
 288                 }
 289         }
 290         return true;
 291 }
 292
 293 /**
 294  * Reads a 24 bpp uncompressed bitmap
 295  */
 296 static inline bool BmpRead24(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 297 {
 298         uint x, y;
 299         byte pad = GB(4 - info->width * 3, 0, 2);
 300         byte *pixel_row;
 301         for (y = info->height; y > 0; y--) {
 302                 pixel_row = &data->bitmap[(y - 1) * info->width * 3];
 303                 for (x = 0; x < info->width; x++) {
 304                         if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
 305                         *(pixel_row + 2) = ReadByte(buffer); // green
 306                         *(pixel_row + 1) = ReadByte(buffer); // blue
 307                         *pixel_row       = ReadByte(buffer); // red
 308                         pixel_row += 3;
 309                 }
 310                 /* Padding for 32 bit align */
 311                 SkipBytes(buffer, pad);
 312         }
 313         return true;
 314 }
 315
 316 /*
 317  * Reads bitmap headers, and palette (if any)
 318  */
 319 bool BmpReadHeader(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 320 {
 321         uint32 header_size;
 322         assert(info != NULL);
 323         MemSetT(info, 0);
 324
 325         /* Reading BMP header */
 326         if (ReadWord(buffer) != 0x4D42) return false; // signature should be 'BM'
 327         SkipBytes(buffer, 8); // skip file size and reserved
 328         info->offset = ReadDword(buffer);
 329
 330         /* Reading info header */
 331         header_size = ReadDword(buffer);
 332         if (header_size < 12) return false; // info header should be at least 12 bytes long
 333
 334         info->os2_bmp = (header_size == 12); // OS/2 1.x or windows 2.x info header is 12 bytes long
 335
 336         if (info->os2_bmp) {
 337                 info->width = ReadWord(buffer);
 338                 info->height = ReadWord(buffer);
 339                 header_size -= 8;
 340         } else {
 341                 info->width = ReadDword(buffer);
 342                 info->height = ReadDword(buffer);
 343                 header_size -= 12;
 344         }
 345
 346         if (ReadWord(buffer) != 1) return false; // BMP can have only 1 plane
 347
 348         info->bpp = ReadWord(buffer);
 349         if (info->bpp != 1 && info->bpp != 4 && info->bpp != 8 && info->bpp != 24) {
 350                 /* Only 1 bpp, 4 bpp, 8bpp and 24 bpp bitmaps are supported */
 351                 return false;
 352         }
 353
 354         /* Reads compression method if available in info header*/
 355         if ((header_size -= 4) >= 4) {
 356                 info->compression = ReadDword(buffer);
 357                 header_size -= 4;
 358         }
 359
 360         /* Only 4-bit and 8-bit rle compression is supported */
 361         if (info->compression > 2 || (info->compression > 0 && !(info->bpp == 4 || info->bpp == 8))) return false;
 362
 363         if (info->bpp <= 8) {
 364                 uint i;
 365
 366                 /* Reads number of colours if available in info header */
 367                 if (header_size >= 16) {
 368                         SkipBytes(buffer, 12);                  // skip image size and resolution
 369                         info->palette_size = ReadDword(buffer); // number of colours in palette
 370                         SkipBytes(buffer, header_size - 16);    // skip the end of info header
 371                 }
 372                 if (info->palette_size == 0) info->palette_size = 1 << info->bpp;
 373
 374                 data->palette = CallocT<Colour>(info->palette_size);
 375
 376                 for (i = 0; i < info->palette_size; i++) {
 377                         data->palette[i].b = ReadByte(buffer);
 378                         data->palette[i].g = ReadByte(buffer);
 379                         data->palette[i].r = ReadByte(buffer);
 380                         if (!info->os2_bmp) SkipBytes(buffer, 1); // unused
 381                 }
 382         }
 383
 384         return buffer->real_pos <= info->offset;
 385 }
 386
 387 /*
 388  * Reads the bitmap
 389  * 1 bpp and 4 bpp bitmaps are converted to 8 bpp bitmaps
 390  */
 391 bool BmpReadBitmap(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 392 {
 393         assert(info != NULL && data != NULL);
 394
 395         data->bitmap = CallocT<byte>(info->width * info->height * ((info->bpp == 24) ? 3 : 1));
 396
 397         /* Load image */
 398         SetStreamOffset(buffer, info->offset);
 399         switch (info->compression) {
 400         case 0: // no compression
 401                 switch (info->bpp) {
 402                 case 1:  return BmpRead1(buffer, info, data);
 403                 case 4:  return BmpRead4(buffer, info, data);
 404                 case 8:  return BmpRead8(buffer, info, data);
 405                 case 24: return BmpRead24(buffer, info, data);
 406                 default: NOT_REACHED();
 407                 }
 408         case 1:  return BmpRead8Rle(buffer, info, data); // 8-bit RLE compression
 409         case 2:  return BmpRead4Rle(buffer, info, data); // 4-bit RLE compression
 410         default: NOT_REACHED();
 411         }
 412 }
 413
 414 void BmpDestroyData(BmpData *data)
 415 {
 416         assert(data != NULL);
 417         free(data->palette);
 418         free(data->bitmap);
 419 }