4 * Copyright (C) 1994-1996, Thomas G. Lane.
5 * Modified 2009-2010 by Guido Vollbeding.
6 * This file is part of the Independent JPEG Group's software.
7 * For conditions of distribution and use, see the accompanying README file.
9 * This file contains routines to read input images in Microsoft "BMP"
10 * format (MS Windows 3.x, OS/2 1.x, and OS/2 2.x flavors).
11 * Currently, only 8-bit and 24-bit images are supported, not 1-bit or
12 * 4-bit (feeding such low-depth images into JPEG would be silly anyway).
13 * Also, we don't support RLE-compressed files.
15 * These routines may need modification for non-Unix environments or
16 * specialized applications. As they stand, they assume input from
17 * an ordinary stdio stream. They further assume that reading begins
18 * at the start of the file; start_input may need work if the
19 * user interface has already read some data (e.g., to determine that
20 * the file is indeed BMP format).
22 * This code contributed by James Arthur Boucher.
25 #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
30 /* Macros to deal with unsigned chars as efficiently as compiler allows */
32 #ifdef HAVE_UNSIGNED_CHAR
33 typedef unsigned char U_CHAR;
34 #define UCH(x) ((int) (x))
35 #else /* !HAVE_UNSIGNED_CHAR */
36 #ifdef CHAR_IS_UNSIGNED
38 #define UCH(x) ((int) (x))
41 #define UCH(x) ((int) (x) & 0xFF)
43 #endif /* HAVE_UNSIGNED_CHAR */
46 #define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
49 /* Private version of data source object */
51 typedef struct _bmp_source_struct * bmp_source_ptr;
53 typedef struct _bmp_source_struct {
54 struct cjpeg_source_struct pub; /* public fields */
56 j_compress_ptr cinfo; /* back link saves passing separate parm */
58 JSAMPARRAY colormap; /* BMP colormap (converted to my format) */
60 jvirt_sarray_ptr whole_image; /* Needed to reverse row order */
61 JDIMENSION source_row; /* Current source row number */
62 JDIMENSION row_width; /* Physical width of scanlines in file */
64 int bits_per_pixel; /* remembers 8- or 24-bit format */
69 read_byte (bmp_source_ptr sinfo)
70 /* Read next byte from BMP file */
72 register FILE *infile = sinfo->pub.input_file;
75 if ((c = getc(infile)) == EOF)
76 ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
82 read_colormap (bmp_source_ptr sinfo, int cmaplen, int mapentrysize)
83 /* Read the colormap from a BMP file */
87 switch (mapentrysize) {
89 /* BGR format (occurs in OS/2 files) */
90 for (i = 0; i < cmaplen; i++) {
91 sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
92 sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
93 sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
97 /* BGR0 format (occurs in MS Windows files) */
98 for (i = 0; i < cmaplen; i++) {
99 sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
100 sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
101 sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
102 (void) read_byte(sinfo);
106 ERREXIT(sinfo->cinfo, JERR_BMP_BADCMAP);
113 * Read one row of pixels.
114 * The image has been read into the whole_image array, but is otherwise
115 * unprocessed. We must read it out in top-to-bottom row order, and if
116 * it is an 8-bit image, we must expand colormapped pixels to 24bit format.
119 METHODDEF(JDIMENSION)
120 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
121 /* This version is for reading 8-bit colormap indexes */
123 bmp_source_ptr source = (bmp_source_ptr) sinfo;
124 register JSAMPARRAY colormap = source->colormap;
125 JSAMPARRAY image_ptr;
127 register JSAMPROW inptr, outptr;
128 register JDIMENSION col;
130 /* Fetch next row from virtual array */
131 source->source_row--;
132 image_ptr = (*cinfo->mem->access_virt_sarray)
133 ((j_common_ptr) cinfo, source->whole_image,
134 source->source_row, (JDIMENSION) 1, FALSE);
136 /* Expand the colormap indexes to real data */
137 inptr = image_ptr[0];
138 outptr = source->pub.buffer[0];
139 for (col = cinfo->image_width; col > 0; col--) {
140 t = GETJSAMPLE(*inptr++);
141 *outptr++ = colormap[0][t]; /* can omit GETJSAMPLE() safely */
142 *outptr++ = colormap[1][t];
143 *outptr++ = colormap[2][t];
150 METHODDEF(JDIMENSION)
151 get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
152 /* This version is for reading 24-bit pixels */
154 bmp_source_ptr source = (bmp_source_ptr) sinfo;
155 JSAMPARRAY image_ptr;
156 register JSAMPROW inptr, outptr;
157 register JDIMENSION col;
159 /* Fetch next row from virtual array */
160 source->source_row--;
161 image_ptr = (*cinfo->mem->access_virt_sarray)
162 ((j_common_ptr) cinfo, source->whole_image,
163 source->source_row, (JDIMENSION) 1, FALSE);
165 /* Transfer data. Note source values are in BGR order
166 * (even though Microsoft's own documents say the opposite).
168 inptr = image_ptr[0];
169 outptr = source->pub.buffer[0];
170 for (col = cinfo->image_width; col > 0; col--) {
171 outptr[2] = *inptr++; /* can omit GETJSAMPLE() safely */
172 outptr[1] = *inptr++;
173 outptr[0] = *inptr++;
181 METHODDEF(JDIMENSION)
182 get_32bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
183 /* This version is for reading 32-bit pixels */
185 bmp_source_ptr source = (bmp_source_ptr) sinfo;
186 JSAMPARRAY image_ptr;
187 register JSAMPROW inptr, outptr;
188 register JDIMENSION col;
190 /* Fetch next row from virtual array */
191 source->source_row--;
192 image_ptr = (*cinfo->mem->access_virt_sarray)
193 ((j_common_ptr) cinfo, source->whole_image,
194 source->source_row, (JDIMENSION) 1, FALSE);
195 /* Transfer data. Note source values are in BGR order
196 * (even though Microsoft's own documents say the opposite).
198 inptr = image_ptr[0];
199 outptr = source->pub.buffer[0];
200 for (col = cinfo->image_width; col > 0; col--) {
201 outptr[2] = *inptr++; /* can omit GETJSAMPLE() safely */
202 outptr[1] = *inptr++;
203 outptr[0] = *inptr++;
204 inptr++; /* skip the 4th byte (Alpha channel) */
213 * This method loads the image into whole_image during the first call on
214 * get_pixel_rows. The get_pixel_rows pointer is then adjusted to call
215 * get_8bit_row, get_24bit_row, or get_32bit_row on subsequent calls.
218 METHODDEF(JDIMENSION)
219 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
221 bmp_source_ptr source = (bmp_source_ptr) sinfo;
222 register FILE *infile = source->pub.input_file;
224 register JSAMPROW out_ptr;
225 JSAMPARRAY image_ptr;
227 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
229 /* Read the data into a virtual array in input-file row order. */
230 for (row = 0; row < cinfo->image_height; row++) {
231 if (progress != NULL) {
232 progress->pub.pass_counter = (long) row;
233 progress->pub.pass_limit = (long) cinfo->image_height;
234 (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
236 image_ptr = (*cinfo->mem->access_virt_sarray)
237 ((j_common_ptr) cinfo, source->whole_image,
238 row, (JDIMENSION) 1, TRUE);
239 out_ptr = image_ptr[0];
240 for (col = source->row_width; col > 0; col--) {
241 /* inline copy of read_byte() for speed */
242 if ((c = getc(infile)) == EOF)
243 ERREXIT(cinfo, JERR_INPUT_EOF);
244 *out_ptr++ = (JSAMPLE) c;
247 if (progress != NULL)
248 progress->completed_extra_passes++;
250 /* Set up to read from the virtual array in top-to-bottom order */
251 switch (source->bits_per_pixel) {
253 source->pub.get_pixel_rows = get_8bit_row;
256 source->pub.get_pixel_rows = get_24bit_row;
259 source->pub.get_pixel_rows = get_32bit_row;
262 ERREXIT(cinfo, JERR_BMP_BADDEPTH);
264 source->source_row = cinfo->image_height;
266 /* And read the first row */
267 return (*source->pub.get_pixel_rows) (cinfo, sinfo);
272 * Read the file header; return image size and component count.
276 start_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
278 bmp_source_ptr source = (bmp_source_ptr) sinfo;
279 U_CHAR bmpfileheader[14];
280 U_CHAR bmpinfoheader[64];
281 #define GET_2B(array,offset) ((unsigned int) UCH(array[offset]) + \
282 (((unsigned int) UCH(array[offset+1])) << 8))
283 #define GET_4B(array,offset) ((INT32) UCH(array[offset]) + \
284 (((INT32) UCH(array[offset+1])) << 8) + \
285 (((INT32) UCH(array[offset+2])) << 16) + \
286 (((INT32) UCH(array[offset+3])) << 24))
291 unsigned int biPlanes;
293 INT32 biXPelsPerMeter,biYPelsPerMeter;
295 int mapentrysize = 0; /* 0 indicates no colormap */
297 JDIMENSION row_width;
299 /* Read and verify the bitmap file header */
300 if (! ReadOK(source->pub.input_file, bmpfileheader, 14))
301 ERREXIT(cinfo, JERR_INPUT_EOF);
302 if (GET_2B(bmpfileheader,0) != 0x4D42) /* 'BM' */
303 ERREXIT(cinfo, JERR_BMP_NOT);
304 bfOffBits = (INT32) GET_4B(bmpfileheader,10);
305 /* We ignore the remaining fileheader fields */
307 /* The infoheader might be 12 bytes (OS/2 1.x), 40 bytes (Windows),
308 * or 64 bytes (OS/2 2.x). Check the first 4 bytes to find out which.
310 if (! ReadOK(source->pub.input_file, bmpinfoheader, 4))
311 ERREXIT(cinfo, JERR_INPUT_EOF);
312 headerSize = (INT32) GET_4B(bmpinfoheader,0);
313 if (headerSize < 12 || headerSize > 64)
314 ERREXIT(cinfo, JERR_BMP_BADHEADER);
315 if (! ReadOK(source->pub.input_file, bmpinfoheader+4, headerSize-4))
316 ERREXIT(cinfo, JERR_INPUT_EOF);
318 switch ((int) headerSize) {
320 /* Decode OS/2 1.x header (Microsoft calls this a BITMAPCOREHEADER) */
321 biWidth = (INT32) GET_2B(bmpinfoheader,4);
322 biHeight = (INT32) GET_2B(bmpinfoheader,6);
323 biPlanes = GET_2B(bmpinfoheader,8);
324 source->bits_per_pixel = (int) GET_2B(bmpinfoheader,10);
326 switch (source->bits_per_pixel) {
327 case 8: /* colormapped image */
328 mapentrysize = 3; /* OS/2 uses RGBTRIPLE colormap */
329 TRACEMS2(cinfo, 1, JTRC_BMP_OS2_MAPPED, (int) biWidth, (int) biHeight);
331 case 24: /* RGB image */
332 TRACEMS2(cinfo, 1, JTRC_BMP_OS2, (int) biWidth, (int) biHeight);
335 ERREXIT(cinfo, JERR_BMP_BADDEPTH);
341 /* Decode Windows 3.x header (Microsoft calls this a BITMAPINFOHEADER) */
342 /* or OS/2 2.x header, which has additional fields that we ignore */
343 biWidth = GET_4B(bmpinfoheader,4);
344 biHeight = GET_4B(bmpinfoheader,8);
345 biPlanes = GET_2B(bmpinfoheader,12);
346 source->bits_per_pixel = (int) GET_2B(bmpinfoheader,14);
347 biCompression = GET_4B(bmpinfoheader,16);
348 biXPelsPerMeter = GET_4B(bmpinfoheader,24);
349 biYPelsPerMeter = GET_4B(bmpinfoheader,28);
350 biClrUsed = GET_4B(bmpinfoheader,32);
351 /* biSizeImage, biClrImportant fields are ignored */
353 switch (source->bits_per_pixel) {
354 case 8: /* colormapped image */
355 mapentrysize = 4; /* Windows uses RGBQUAD colormap */
356 TRACEMS2(cinfo, 1, JTRC_BMP_MAPPED, (int) biWidth, (int) biHeight);
358 case 24: /* RGB image */
359 TRACEMS2(cinfo, 1, JTRC_BMP, (int) biWidth, (int) biHeight);
361 case 32: /* RGB image + Alpha channel */
362 TRACEMS2(cinfo, 1, JTRC_BMP, (int) biWidth, (int) biHeight);
365 ERREXIT(cinfo, JERR_BMP_BADDEPTH);
368 if (biCompression != 0)
369 ERREXIT(cinfo, JERR_BMP_COMPRESSED);
371 if (biXPelsPerMeter > 0 && biYPelsPerMeter > 0) {
372 /* Set JFIF density parameters from the BMP data */
373 cinfo->X_density = (UINT16) (biXPelsPerMeter/100); /* 100 cm per meter */
374 cinfo->Y_density = (UINT16) (biYPelsPerMeter/100);
375 cinfo->density_unit = 2; /* dots/cm */
379 ERREXIT(cinfo, JERR_BMP_BADHEADER);
383 if (biWidth <= 0 || biHeight <= 0)
384 ERREXIT(cinfo, JERR_BMP_EMPTY);
386 ERREXIT(cinfo, JERR_BMP_BADPLANES);
388 /* Compute distance to bitmap data --- will adjust for colormap below */
389 bPad = bfOffBits - (headerSize + 14);
391 /* Read the colormap, if any */
392 if (mapentrysize > 0) {
394 biClrUsed = 256; /* assume it's 256 */
395 else if (biClrUsed > 256)
396 ERREXIT(cinfo, JERR_BMP_BADCMAP);
397 /* Allocate space to store the colormap */
398 source->colormap = (*cinfo->mem->alloc_sarray)
399 ((j_common_ptr) cinfo, JPOOL_IMAGE,
400 (JDIMENSION) biClrUsed, (JDIMENSION) 3);
401 /* and read it from the file */
402 read_colormap(source, (int) biClrUsed, mapentrysize);
403 /* account for size of colormap */
404 bPad -= biClrUsed * mapentrysize;
407 /* Skip any remaining pad bytes */
408 if (bPad < 0) /* incorrect bfOffBits value? */
409 ERREXIT(cinfo, JERR_BMP_BADHEADER);
410 while (--bPad >= 0) {
411 (void) read_byte(source);
414 /* Compute row width in file, including padding to 4-byte boundary */
415 if (source->bits_per_pixel == 24)
416 row_width = (JDIMENSION) (biWidth * 3);
417 else if (source->bits_per_pixel == 32)
418 row_width = (JDIMENSION) (biWidth * 4);
420 row_width = (JDIMENSION) biWidth;
421 while ((row_width & 3) != 0) row_width++;
422 source->row_width = row_width;
424 /* Allocate space for inversion array, prepare for preload pass */
425 source->whole_image = (*cinfo->mem->request_virt_sarray)
426 ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
427 row_width, (JDIMENSION) biHeight, (JDIMENSION) 1);
428 source->pub.get_pixel_rows = preload_image;
429 if (cinfo->progress != NULL) {
430 cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
431 progress->total_extra_passes++; /* count file input as separate pass */
434 /* Allocate one-row buffer for returned data */
435 source->pub.buffer = (*cinfo->mem->alloc_sarray)
436 ((j_common_ptr) cinfo, JPOOL_IMAGE,
437 (JDIMENSION) (biWidth * 3), (JDIMENSION) 1);
438 source->pub.buffer_height = 1;
440 cinfo->in_color_space = JCS_RGB;
441 cinfo->input_components = 3;
442 cinfo->data_precision = 8;
443 cinfo->image_width = (JDIMENSION) biWidth;
444 cinfo->image_height = (JDIMENSION) biHeight;
449 * Finish up at the end of the file.
453 finish_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
460 * The module selection routine for BMP format input.
463 GLOBAL(cjpeg_source_ptr)
464 jinit_read_bmp (j_compress_ptr cinfo)
466 bmp_source_ptr source;
468 /* Create module interface object */
469 source = (bmp_source_ptr)
470 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
471 SIZEOF(bmp_source_struct));
472 source->cinfo = cinfo; /* make back link for subroutines */
473 /* Fill in method ptrs, except get_pixel_rows which start_input sets */
474 source->pub.start_input = start_input_bmp;
475 source->pub.finish_input = finish_input_bmp;
477 return (cjpeg_source_ptr) source;
480 #endif /* BMP_SUPPORTED */