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      1 /*
      2  * rdbmp.c
      3  *
      4  * Copyright (C) 1994-1996, Thomas G. Lane.
      5  * This file is part of the Independent JPEG Group's software.
      6  * For conditions of distribution and use, see the accompanying README file.
      7  *
      8  * This file contains routines to read input images in Microsoft "BMP"
      9  * format (MS Windows 3.x, OS/2 1.x, and OS/2 2.x flavors).
     10  * Currently, only 8-bit and 24-bit images are supported, not 1-bit or
     11  * 4-bit (feeding such low-depth images into JPEG would be silly anyway).
     12  * Also, we don't support RLE-compressed files.
     13  *
     14  * These routines may need modification for non-Unix environments or
     15  * specialized applications.  As they stand, they assume input from
     16  * an ordinary stdio stream.  They further assume that reading begins
     17  * at the start of the file; start_input may need work if the
     18  * user interface has already read some data (e.g., to determine that
     19  * the file is indeed BMP format).
     20  *
     21  * This code contributed by James Arthur Boucher.
     22  */
     23 
     24 #include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */
     25 
     26 #ifdef BMP_SUPPORTED
     27 
     28 
     29 /* Macros to deal with unsigned chars as efficiently as compiler allows */
     30 
     31 #ifdef HAVE_UNSIGNED_CHAR
     32 typedef unsigned char U_CHAR;
     33 #define UCH(x)	((int) (x))
     34 #else /* !HAVE_UNSIGNED_CHAR */
     35 #ifdef CHAR_IS_UNSIGNED
     36 typedef char U_CHAR;
     37 #define UCH(x)	((int) (x))
     38 #else
     39 typedef char U_CHAR;
     40 #define UCH(x)	((int) (x) & 0xFF)
     41 #endif
     42 #endif /* HAVE_UNSIGNED_CHAR */
     43 
     44 
     45 #define	ReadOK(file,buffer,len)	(JFREAD(file,buffer,len) == ((size_t) (len)))
     46 
     47 
     48 /* Private version of data source object */
     49 
     50 typedef struct _bmp_source_struct * bmp_source_ptr;
     51 
     52 typedef struct _bmp_source_struct {
     53   struct cjpeg_source_struct pub; /* public fields */
     54 
     55   j_compress_ptr cinfo;		/* back link saves passing separate parm */
     56 
     57   JSAMPARRAY colormap;		/* BMP colormap (converted to my format) */
     58 
     59   jvirt_sarray_ptr whole_image;	/* Needed to reverse row order */
     60   JDIMENSION source_row;	/* Current source row number */
     61   JDIMENSION row_width;		/* Physical width of scanlines in file */
     62 
     63   int bits_per_pixel;		/* remembers 8- or 24-bit format */
     64 } bmp_source_struct;
     65 
     66 
     67 LOCAL(int)
     68 read_byte (bmp_source_ptr sinfo)
     69 /* Read next byte from BMP file */
     70 {
     71   register FILE *infile = sinfo->pub.input_file;
     72   register int c;
     73 
     74   if ((c = getc(infile)) == EOF)
     75     ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
     76   return c;
     77 }
     78 
     79 
     80 LOCAL(void)
     81 read_colormap (bmp_source_ptr sinfo, int cmaplen, int mapentrysize)
     82 /* Read the colormap from a BMP file */
     83 {
     84   int i;
     85 
     86   switch (mapentrysize) {
     87   case 3:
     88     /* BGR format (occurs in OS/2 files) */
     89     for (i = 0; i < cmaplen; i++) {
     90       sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
     91       sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
     92       sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
     93     }
     94     break;
     95   case 4:
     96     /* BGR0 format (occurs in MS Windows files) */
     97     for (i = 0; i < cmaplen; i++) {
     98       sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
     99       sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
    100       sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
    101       (void) read_byte(sinfo);
    102     }
    103     break;
    104   default:
    105     ERREXIT(sinfo->cinfo, JERR_BMP_BADCMAP);
    106     break;
    107   }
    108 }
    109 
    110 
    111 /*
    112  * Read one row of pixels.
    113  * The image has been read into the whole_image array, but is otherwise
    114  * unprocessed.  We must read it out in top-to-bottom row order, and if
    115  * it is an 8-bit image, we must expand colormapped pixels to 24bit format.
    116  */
    117 
    118 METHODDEF(JDIMENSION)
    119 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
    120 /* This version is for reading 8-bit colormap indexes */
    121 {
    122   bmp_source_ptr source = (bmp_source_ptr) sinfo;
    123   register JSAMPARRAY colormap = source->colormap;
    124   JSAMPARRAY image_ptr;
    125   register int t;
    126   register JSAMPROW inptr, outptr;
    127   register JDIMENSION col;
    128 
    129   /* Fetch next row from virtual array */
    130   source->source_row--;
    131   image_ptr = (*cinfo->mem->access_virt_sarray)
    132     ((j_common_ptr) cinfo, source->whole_image,
    133      source->source_row, (JDIMENSION) 1, FALSE);
    134 
    135   /* Expand the colormap indexes to real data */
    136   inptr = image_ptr[0];
    137   outptr = source->pub.buffer[0];
    138   for (col = cinfo->image_width; col > 0; col--) {
    139     t = GETJSAMPLE(*inptr++);
    140     *outptr++ = colormap[0][t];	/* can omit GETJSAMPLE() safely */
    141     *outptr++ = colormap[1][t];
    142     *outptr++ = colormap[2][t];
    143   }
    144 
    145   return 1;
    146 }
    147 
    148 
    149 METHODDEF(JDIMENSION)
    150 get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
    151 /* This version is for reading 24-bit pixels */
    152 {
    153   bmp_source_ptr source = (bmp_source_ptr) sinfo;
    154   JSAMPARRAY image_ptr;
    155   register JSAMPROW inptr, outptr;
    156   register JDIMENSION col;
    157 
    158   /* Fetch next row from virtual array */
    159   source->source_row--;
    160   image_ptr = (*cinfo->mem->access_virt_sarray)
    161     ((j_common_ptr) cinfo, source->whole_image,
    162      source->source_row, (JDIMENSION) 1, FALSE);
    163 
    164   /* Transfer data.  Note source values are in BGR order
    165    * (even though Microsoft's own documents say the opposite).
    166    */
    167   inptr = image_ptr[0];
    168   outptr = source->pub.buffer[0];
    169   for (col = cinfo->image_width; col > 0; col--) {
    170     outptr[2] = *inptr++;	/* can omit GETJSAMPLE() safely */
    171     outptr[1] = *inptr++;
    172     outptr[0] = *inptr++;
    173     outptr += 3;
    174   }
    175 
    176   return 1;
    177 }
    178 
    179 
    180 /*
    181  * This method loads the image into whole_image during the first call on
    182  * get_pixel_rows.  The get_pixel_rows pointer is then adjusted to call
    183  * get_8bit_row or get_24bit_row on subsequent calls.
    184  */
    185 
    186 METHODDEF(JDIMENSION)
    187 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
    188 {
    189   bmp_source_ptr source = (bmp_source_ptr) sinfo;
    190   register FILE *infile = source->pub.input_file;
    191   register int c;
    192   register JSAMPROW out_ptr;
    193   JSAMPARRAY image_ptr;
    194   JDIMENSION row, col;
    195   cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
    196 
    197   /* Read the data into a virtual array in input-file row order. */
    198   for (row = 0; row < cinfo->image_height; row++) {
    199     if (progress != NULL) {
    200       progress->pub.pass_counter = (long) row;
    201       progress->pub.pass_limit = (long) cinfo->image_height;
    202       (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
    203     }
    204     image_ptr = (*cinfo->mem->access_virt_sarray)
    205       ((j_common_ptr) cinfo, source->whole_image,
    206        row, (JDIMENSION) 1, TRUE);
    207     out_ptr = image_ptr[0];
    208     for (col = source->row_width; col > 0; col--) {
    209       /* inline copy of read_byte() for speed */
    210       if ((c = getc(infile)) == EOF)
    211 	ERREXIT(cinfo, JERR_INPUT_EOF);
    212       *out_ptr++ = (JSAMPLE) c;
    213     }
    214   }
    215   if (progress != NULL)
    216     progress->completed_extra_passes++;
    217 
    218   /* Set up to read from the virtual array in top-to-bottom order */
    219   switch (source->bits_per_pixel) {
    220   case 8:
    221     source->pub.get_pixel_rows = get_8bit_row;
    222     break;
    223   case 24:
    224     source->pub.get_pixel_rows = get_24bit_row;
    225     break;
    226   default:
    227     ERREXIT(cinfo, JERR_BMP_BADDEPTH);
    228   }
    229   source->source_row = cinfo->image_height;
    230 
    231   /* And read the first row */
    232   return (*source->pub.get_pixel_rows) (cinfo, sinfo);
    233 }
    234 
    235 
    236 /*
    237  * Read the file header; return image size and component count.
    238  */
    239 
    240 METHODDEF(void)
    241 start_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
    242 {
    243   bmp_source_ptr source = (bmp_source_ptr) sinfo;
    244   U_CHAR bmpfileheader[14];
    245   U_CHAR bmpinfoheader[64];
    246 #define GET_2B(array,offset)  ((unsigned int) UCH(array[offset]) + \
    247 			       (((unsigned int) UCH(array[offset+1])) << 8))
    248 #define GET_4B(array,offset)  ((INT32) UCH(array[offset]) + \
    249 			       (((INT32) UCH(array[offset+1])) << 8) + \
    250 			       (((INT32) UCH(array[offset+2])) << 16) + \
    251 			       (((INT32) UCH(array[offset+3])) << 24))
    252   INT32 bfOffBits;
    253   INT32 headerSize;
    254   INT32 biWidth = 0;		/* initialize to avoid compiler warning */
    255   INT32 biHeight = 0;
    256   unsigned int biPlanes;
    257   INT32 biCompression;
    258   INT32 biXPelsPerMeter,biYPelsPerMeter;
    259   INT32 biClrUsed = 0;
    260   int mapentrysize = 0;		/* 0 indicates no colormap */
    261   INT32 bPad;
    262   JDIMENSION row_width;
    263 
    264   /* Read and verify the bitmap file header */
    265   if (! ReadOK(source->pub.input_file, bmpfileheader, 14))
    266     ERREXIT(cinfo, JERR_INPUT_EOF);
    267   if (GET_2B(bmpfileheader,0) != 0x4D42) /* 'BM' */
    268     ERREXIT(cinfo, JERR_BMP_NOT);
    269   bfOffBits = (INT32) GET_4B(bmpfileheader,10);
    270   /* We ignore the remaining fileheader fields */
    271 
    272   /* The infoheader might be 12 bytes (OS/2 1.x), 40 bytes (Windows),
    273    * or 64 bytes (OS/2 2.x).  Check the first 4 bytes to find out which.
    274    */
    275   if (! ReadOK(source->pub.input_file, bmpinfoheader, 4))
    276     ERREXIT(cinfo, JERR_INPUT_EOF);
    277   headerSize = (INT32) GET_4B(bmpinfoheader,0);
    278   if (headerSize < 12 || headerSize > 64)
    279     ERREXIT(cinfo, JERR_BMP_BADHEADER);
    280   if (! ReadOK(source->pub.input_file, bmpinfoheader+4, headerSize-4))
    281     ERREXIT(cinfo, JERR_INPUT_EOF);
    282 
    283   switch ((int) headerSize) {
    284   case 12:
    285     /* Decode OS/2 1.x header (Microsoft calls this a BITMAPCOREHEADER) */
    286     biWidth = (INT32) GET_2B(bmpinfoheader,4);
    287     biHeight = (INT32) GET_2B(bmpinfoheader,6);
    288     biPlanes = GET_2B(bmpinfoheader,8);
    289     source->bits_per_pixel = (int) GET_2B(bmpinfoheader,10);
    290 
    291     switch (source->bits_per_pixel) {
    292     case 8:			/* colormapped image */
    293       mapentrysize = 3;		/* OS/2 uses RGBTRIPLE colormap */
    294       TRACEMS2(cinfo, 1, JTRC_BMP_OS2_MAPPED, (int) biWidth, (int) biHeight);
    295       break;
    296     case 24:			/* RGB image */
    297       TRACEMS2(cinfo, 1, JTRC_BMP_OS2, (int) biWidth, (int) biHeight);
    298       break;
    299     default:
    300       ERREXIT(cinfo, JERR_BMP_BADDEPTH);
    301       break;
    302     }
    303     if (biPlanes != 1)
    304       ERREXIT(cinfo, JERR_BMP_BADPLANES);
    305     break;
    306   case 40:
    307   case 64:
    308     /* Decode Windows 3.x header (Microsoft calls this a BITMAPINFOHEADER) */
    309     /* or OS/2 2.x header, which has additional fields that we ignore */
    310     biWidth = GET_4B(bmpinfoheader,4);
    311     biHeight = GET_4B(bmpinfoheader,8);
    312     biPlanes = GET_2B(bmpinfoheader,12);
    313     source->bits_per_pixel = (int) GET_2B(bmpinfoheader,14);
    314     biCompression = GET_4B(bmpinfoheader,16);
    315     biXPelsPerMeter = GET_4B(bmpinfoheader,24);
    316     biYPelsPerMeter = GET_4B(bmpinfoheader,28);
    317     biClrUsed = GET_4B(bmpinfoheader,32);
    318     /* biSizeImage, biClrImportant fields are ignored */
    319 
    320     switch (source->bits_per_pixel) {
    321     case 8:			/* colormapped image */
    322       mapentrysize = 4;		/* Windows uses RGBQUAD colormap */
    323       TRACEMS2(cinfo, 1, JTRC_BMP_MAPPED, (int) biWidth, (int) biHeight);
    324       break;
    325     case 24:			/* RGB image */
    326       TRACEMS2(cinfo, 1, JTRC_BMP, (int) biWidth, (int) biHeight);
    327       break;
    328     default:
    329       ERREXIT(cinfo, JERR_BMP_BADDEPTH);
    330       break;
    331     }
    332     if (biPlanes != 1)
    333       ERREXIT(cinfo, JERR_BMP_BADPLANES);
    334     if (biCompression != 0)
    335       ERREXIT(cinfo, JERR_BMP_COMPRESSED);
    336 
    337     if (biXPelsPerMeter > 0 && biYPelsPerMeter > 0) {
    338       /* Set JFIF density parameters from the BMP data */
    339       cinfo->X_density = (UINT16) (biXPelsPerMeter/100); /* 100 cm per meter */
    340       cinfo->Y_density = (UINT16) (biYPelsPerMeter/100);
    341       cinfo->density_unit = 2;	/* dots/cm */
    342     }
    343     break;
    344   default:
    345     ERREXIT(cinfo, JERR_BMP_BADHEADER);
    346     break;
    347   }
    348 
    349   /* Compute distance to bitmap data --- will adjust for colormap below */
    350   bPad = bfOffBits - (headerSize + 14);
    351 
    352   /* Read the colormap, if any */
    353   if (mapentrysize > 0) {
    354     if (biClrUsed <= 0)
    355       biClrUsed = 256;		/* assume it's 256 */
    356     else if (biClrUsed > 256)
    357       ERREXIT(cinfo, JERR_BMP_BADCMAP);
    358     /* Allocate space to store the colormap */
    359     source->colormap = (*cinfo->mem->alloc_sarray)
    360       ((j_common_ptr) cinfo, JPOOL_IMAGE,
    361        (JDIMENSION) biClrUsed, (JDIMENSION) 3);
    362     /* and read it from the file */
    363     read_colormap(source, (int) biClrUsed, mapentrysize);
    364     /* account for size of colormap */
    365     bPad -= biClrUsed * mapentrysize;
    366   }
    367 
    368   /* Skip any remaining pad bytes */
    369   if (bPad < 0)			/* incorrect bfOffBits value? */
    370     ERREXIT(cinfo, JERR_BMP_BADHEADER);
    371   while (--bPad >= 0) {
    372     (void) read_byte(source);
    373   }
    374 
    375   /* Compute row width in file, including padding to 4-byte boundary */
    376   if (source->bits_per_pixel == 24)
    377     row_width = (JDIMENSION) (biWidth * 3);
    378   else
    379     row_width = (JDIMENSION) biWidth;
    380   while ((row_width & 3) != 0) row_width++;
    381   source->row_width = row_width;
    382 
    383   /* Allocate space for inversion array, prepare for preload pass */
    384   source->whole_image = (*cinfo->mem->request_virt_sarray)
    385     ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
    386      row_width, (JDIMENSION) biHeight, (JDIMENSION) 1);
    387   source->pub.get_pixel_rows = preload_image;
    388   if (cinfo->progress != NULL) {
    389     cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
    390     progress->total_extra_passes++; /* count file input as separate pass */
    391   }
    392 
    393   /* Allocate one-row buffer for returned data */
    394   source->pub.buffer = (*cinfo->mem->alloc_sarray)
    395     ((j_common_ptr) cinfo, JPOOL_IMAGE,
    396      (JDIMENSION) (biWidth * 3), (JDIMENSION) 1);
    397   source->pub.buffer_height = 1;
    398 
    399   cinfo->in_color_space = JCS_RGB;
    400   cinfo->input_components = 3;
    401   cinfo->data_precision = 8;
    402   cinfo->image_width = (JDIMENSION) biWidth;
    403   cinfo->image_height = (JDIMENSION) biHeight;
    404 }
    405 
    406 
    407 /*
    408  * Finish up at the end of the file.
    409  */
    410 
    411 METHODDEF(void)
    412 finish_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
    413 {
    414   /* no work */
    415 }
    416 
    417 
    418 /*
    419  * The module selection routine for BMP format input.
    420  */
    421 
    422 GLOBAL(cjpeg_source_ptr)
    423 jinit_read_bmp (j_compress_ptr cinfo)
    424 {
    425   bmp_source_ptr source;
    426 
    427   /* Create module interface object */
    428   source = (bmp_source_ptr)
    429       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
    430 				  SIZEOF(bmp_source_struct));
    431   source->cinfo = cinfo;	/* make back link for subroutines */
    432   /* Fill in method ptrs, except get_pixel_rows which start_input sets */
    433   source->pub.start_input = start_input_bmp;
    434   source->pub.finish_input = finish_input_bmp;
    435 
    436   return (cjpeg_source_ptr) source;
    437 }
    438 
    439 #endif /* BMP_SUPPORTED */
    440