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plt-scheme  4.2.1
rdbmp.c
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00001 /*
00002  * rdbmp.c
00003  *
00004  * Copyright (C) 1994-1996, Thomas G. Lane.
00005  * This file is part of the Independent JPEG Group's software.
00006  * For conditions of distribution and use, see the accompanying README file.
00007  *
00008  * This file contains routines to read input images in Microsoft "BMP"
00009  * format (MS Windows 3.x, OS/2 1.x, and OS/2 2.x flavors).
00010  * Currently, only 8-bit and 24-bit images are supported, not 1-bit or
00011  * 4-bit (feeding such low-depth images into JPEG would be silly anyway).
00012  * Also, we don't support RLE-compressed files.
00013  *
00014  * These routines may need modification for non-Unix environments or
00015  * specialized applications.  As they stand, they assume input from
00016  * an ordinary stdio stream.  They further assume that reading begins
00017  * at the start of the file; start_input may need work if the
00018  * user interface has already read some data (e.g., to determine that
00019  * the file is indeed BMP format).
00020  *
00021  * This code contributed by James Arthur Boucher.
00022  */
00023 
00024 #include "cdjpeg.h"         /* Common decls for cjpeg/djpeg applications */
00025 
00026 #ifdef BMP_SUPPORTED
00027 
00028 
00029 /* Macros to deal with unsigned chars as efficiently as compiler allows */
00030 
00031 #ifdef HAVE_UNSIGNED_CHAR
00032 typedef unsigned char U_CHAR;
00033 #define UCH(x)       ((int) (x))
00034 #else /* !HAVE_UNSIGNED_CHAR */
00035 #ifdef CHAR_IS_UNSIGNED
00036 typedef char U_CHAR;
00037 #define UCH(x)       ((int) (x))
00038 #else
00039 typedef char U_CHAR;
00040 #define UCH(x)       ((int) (x) & 0xFF)
00041 #endif
00042 #endif /* HAVE_UNSIGNED_CHAR */
00043 
00044 
00045 #define       ReadOK(file,buffer,len)     (JFREAD(file,buffer,len) == ((size_t) (len)))
00046 
00047 
00048 /* Private version of data source object */
00049 
00050 typedef struct _bmp_source_struct * bmp_source_ptr;
00051 
00052 typedef struct _bmp_source_struct {
00053   struct cjpeg_source_struct pub; /* public fields */
00054 
00055   j_compress_ptr cinfo;            /* back link saves passing separate parm */
00056 
00057   JSAMPARRAY colormap;             /* BMP colormap (converted to my format) */
00058 
00059   jvirt_sarray_ptr whole_image;    /* Needed to reverse row order */
00060   JDIMENSION source_row;    /* Current source row number */
00061   JDIMENSION row_width;            /* Physical width of scanlines in file */
00062 
00063   int bits_per_pixel;              /* remembers 8- or 24-bit format */
00064 } bmp_source_struct;
00065 
00066 
00067 LOCAL(int)
00068 read_byte (bmp_source_ptr sinfo)
00069 /* Read next byte from BMP file */
00070 {
00071   register FILE *infile = sinfo->pub.input_file;
00072   register int c;
00073 
00074   if ((c = getc(infile)) == EOF)
00075     ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
00076   return c;
00077 }
00078 
00079 
00080 LOCAL(void)
00081 read_colormap (bmp_source_ptr sinfo, int cmaplen, int mapentrysize)
00082 /* Read the colormap from a BMP file */
00083 {
00084   int i;
00085 
00086   switch (mapentrysize) {
00087   case 3:
00088     /* BGR format (occurs in OS/2 files) */
00089     for (i = 0; i < cmaplen; i++) {
00090       sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
00091       sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
00092       sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
00093     }
00094     break;
00095   case 4:
00096     /* BGR0 format (occurs in MS Windows files) */
00097     for (i = 0; i < cmaplen; i++) {
00098       sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
00099       sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
00100       sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
00101       (void) read_byte(sinfo);
00102     }
00103     break;
00104   default:
00105     ERREXIT(sinfo->cinfo, JERR_BMP_BADCMAP);
00106     break;
00107   }
00108 }
00109 
00110 
00111 /*
00112  * Read one row of pixels.
00113  * The image has been read into the whole_image array, but is otherwise
00114  * unprocessed.  We must read it out in top-to-bottom row order, and if
00115  * it is an 8-bit image, we must expand colormapped pixels to 24bit format.
00116  */
00117 
00118 METHODDEF(JDIMENSION)
00119 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00120 /* This version is for reading 8-bit colormap indexes */
00121 {
00122   bmp_source_ptr source = (bmp_source_ptr) sinfo;
00123   register JSAMPARRAY colormap = source->colormap;
00124   JSAMPARRAY image_ptr;
00125   register int t;
00126   register JSAMPROW inptr, outptr;
00127   register JDIMENSION col;
00128 
00129   /* Fetch next row from virtual array */
00130   source->source_row--;
00131   image_ptr = (*cinfo->mem->access_virt_sarray)
00132     ((j_common_ptr) cinfo, source->whole_image,
00133      source->source_row, (JDIMENSION) 1, FALSE);
00134 
00135   /* Expand the colormap indexes to real data */
00136   inptr = image_ptr[0];
00137   outptr = source->pub.buffer[0];
00138   for (col = cinfo->image_width; col > 0; col--) {
00139     t = GETJSAMPLE(*inptr++);
00140     *outptr++ = colormap[0][t];    /* can omit GETJSAMPLE() safely */
00141     *outptr++ = colormap[1][t];
00142     *outptr++ = colormap[2][t];
00143   }
00144 
00145   return 1;
00146 }
00147 
00148 
00149 METHODDEF(JDIMENSION)
00150 get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00151 /* This version is for reading 24-bit pixels */
00152 {
00153   bmp_source_ptr source = (bmp_source_ptr) sinfo;
00154   JSAMPARRAY image_ptr;
00155   register JSAMPROW inptr, outptr;
00156   register JDIMENSION col;
00157 
00158   /* Fetch next row from virtual array */
00159   source->source_row--;
00160   image_ptr = (*cinfo->mem->access_virt_sarray)
00161     ((j_common_ptr) cinfo, source->whole_image,
00162      source->source_row, (JDIMENSION) 1, FALSE);
00163 
00164   /* Transfer data.  Note source values are in BGR order
00165    * (even though Microsoft's own documents say the opposite).
00166    */
00167   inptr = image_ptr[0];
00168   outptr = source->pub.buffer[0];
00169   for (col = cinfo->image_width; col > 0; col--) {
00170     outptr[2] = *inptr++;   /* can omit GETJSAMPLE() safely */
00171     outptr[1] = *inptr++;
00172     outptr[0] = *inptr++;
00173     outptr += 3;
00174   }
00175 
00176   return 1;
00177 }
00178 
00179 
00180 /*
00181  * This method loads the image into whole_image during the first call on
00182  * get_pixel_rows.  The get_pixel_rows pointer is then adjusted to call
00183  * get_8bit_row or get_24bit_row on subsequent calls.
00184  */
00185 
00186 METHODDEF(JDIMENSION)
00187 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00188 {
00189   bmp_source_ptr source = (bmp_source_ptr) sinfo;
00190   register FILE *infile = source->pub.input_file;
00191   register int c;
00192   register JSAMPROW out_ptr;
00193   JSAMPARRAY image_ptr;
00194   JDIMENSION row, col;
00195   cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
00196 
00197   /* Read the data into a virtual array in input-file row order. */
00198   for (row = 0; row < cinfo->image_height; row++) {
00199     if (progress != NULL) {
00200       progress->pub.pass_counter = (long) row;
00201       progress->pub.pass_limit = (long) cinfo->image_height;
00202       (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
00203     }
00204     image_ptr = (*cinfo->mem->access_virt_sarray)
00205       ((j_common_ptr) cinfo, source->whole_image,
00206        row, (JDIMENSION) 1, TRUE);
00207     out_ptr = image_ptr[0];
00208     for (col = source->row_width; col > 0; col--) {
00209       /* inline copy of read_byte() for speed */
00210       if ((c = getc(infile)) == EOF)
00211        ERREXIT(cinfo, JERR_INPUT_EOF);
00212       *out_ptr++ = (JSAMPLE) c;
00213     }
00214   }
00215   if (progress != NULL)
00216     progress->completed_extra_passes++;
00217 
00218   /* Set up to read from the virtual array in top-to-bottom order */
00219   switch (source->bits_per_pixel) {
00220   case 8:
00221     source->pub.get_pixel_rows = get_8bit_row;
00222     break;
00223   case 24:
00224     source->pub.get_pixel_rows = get_24bit_row;
00225     break;
00226   default:
00227     ERREXIT(cinfo, JERR_BMP_BADDEPTH);
00228   }
00229   source->source_row = cinfo->image_height;
00230 
00231   /* And read the first row */
00232   return (*source->pub.get_pixel_rows) (cinfo, sinfo);
00233 }
00234 
00235 
00236 /*
00237  * Read the file header; return image size and component count.
00238  */
00239 
00240 METHODDEF(void)
00241 start_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00242 {
00243   bmp_source_ptr source = (bmp_source_ptr) sinfo;
00244   U_CHAR bmpfileheader[14];
00245   U_CHAR bmpinfoheader[64];
00246 #define GET_2B(array,offset)  ((unsigned int) UCH(array[offset]) + \
00247                             (((unsigned int) UCH(array[offset+1])) << 8))
00248 #define GET_4B(array,offset)  ((INT32) UCH(array[offset]) + \
00249                             (((INT32) UCH(array[offset+1])) << 8) + \
00250                             (((INT32) UCH(array[offset+2])) << 16) + \
00251                             (((INT32) UCH(array[offset+3])) << 24))
00252   INT32 bfOffBits;
00253   INT32 headerSize;
00254   INT32 biWidth = 0;        /* initialize to avoid compiler warning */
00255   INT32 biHeight = 0;
00256   unsigned int biPlanes;
00257   INT32 biCompression;
00258   INT32 biXPelsPerMeter,biYPelsPerMeter;
00259   INT32 biClrUsed = 0;
00260   int mapentrysize = 0;            /* 0 indicates no colormap */
00261   INT32 bPad;
00262   JDIMENSION row_width;
00263 
00264   /* Read and verify the bitmap file header */
00265   if (! ReadOK(source->pub.input_file, bmpfileheader, 14))
00266     ERREXIT(cinfo, JERR_INPUT_EOF);
00267   if (GET_2B(bmpfileheader,0) != 0x4D42) /* 'BM' */
00268     ERREXIT(cinfo, JERR_BMP_NOT);
00269   bfOffBits = (INT32) GET_4B(bmpfileheader,10);
00270   /* We ignore the remaining fileheader fields */
00271 
00272   /* The infoheader might be 12 bytes (OS/2 1.x), 40 bytes (Windows),
00273    * or 64 bytes (OS/2 2.x).  Check the first 4 bytes to find out which.
00274    */
00275   if (! ReadOK(source->pub.input_file, bmpinfoheader, 4))
00276     ERREXIT(cinfo, JERR_INPUT_EOF);
00277   headerSize = (INT32) GET_4B(bmpinfoheader,0);
00278   if (headerSize < 12 || headerSize > 64)
00279     ERREXIT(cinfo, JERR_BMP_BADHEADER);
00280   if (! ReadOK(source->pub.input_file, bmpinfoheader+4, headerSize-4))
00281     ERREXIT(cinfo, JERR_INPUT_EOF);
00282 
00283   switch ((int) headerSize) {
00284   case 12:
00285     /* Decode OS/2 1.x header (Microsoft calls this a BITMAPCOREHEADER) */
00286     biWidth = (INT32) GET_2B(bmpinfoheader,4);
00287     biHeight = (INT32) GET_2B(bmpinfoheader,6);
00288     biPlanes = GET_2B(bmpinfoheader,8);
00289     source->bits_per_pixel = (int) GET_2B(bmpinfoheader,10);
00290 
00291     switch (source->bits_per_pixel) {
00292     case 8:                 /* colormapped image */
00293       mapentrysize = 3;            /* OS/2 uses RGBTRIPLE colormap */
00294       TRACEMS2(cinfo, 1, JTRC_BMP_OS2_MAPPED, (int) biWidth, (int) biHeight);
00295       break;
00296     case 24:                /* RGB image */
00297       TRACEMS2(cinfo, 1, JTRC_BMP_OS2, (int) biWidth, (int) biHeight);
00298       break;
00299     default:
00300       ERREXIT(cinfo, JERR_BMP_BADDEPTH);
00301       break;
00302     }
00303     if (biPlanes != 1)
00304       ERREXIT(cinfo, JERR_BMP_BADPLANES);
00305     break;
00306   case 40:
00307   case 64:
00308     /* Decode Windows 3.x header (Microsoft calls this a BITMAPINFOHEADER) */
00309     /* or OS/2 2.x header, which has additional fields that we ignore */
00310     biWidth = GET_4B(bmpinfoheader,4);
00311     biHeight = GET_4B(bmpinfoheader,8);
00312     biPlanes = GET_2B(bmpinfoheader,12);
00313     source->bits_per_pixel = (int) GET_2B(bmpinfoheader,14);
00314     biCompression = GET_4B(bmpinfoheader,16);
00315     biXPelsPerMeter = GET_4B(bmpinfoheader,24);
00316     biYPelsPerMeter = GET_4B(bmpinfoheader,28);
00317     biClrUsed = GET_4B(bmpinfoheader,32);
00318     /* biSizeImage, biClrImportant fields are ignored */
00319 
00320     switch (source->bits_per_pixel) {
00321     case 8:                 /* colormapped image */
00322       mapentrysize = 4;            /* Windows uses RGBQUAD colormap */
00323       TRACEMS2(cinfo, 1, JTRC_BMP_MAPPED, (int) biWidth, (int) biHeight);
00324       break;
00325     case 24:                /* RGB image */
00326       TRACEMS2(cinfo, 1, JTRC_BMP, (int) biWidth, (int) biHeight);
00327       break;
00328     default:
00329       ERREXIT(cinfo, JERR_BMP_BADDEPTH);
00330       break;
00331     }
00332     if (biPlanes != 1)
00333       ERREXIT(cinfo, JERR_BMP_BADPLANES);
00334     if (biCompression != 0)
00335       ERREXIT(cinfo, JERR_BMP_COMPRESSED);
00336 
00337     if (biXPelsPerMeter > 0 && biYPelsPerMeter > 0) {
00338       /* Set JFIF density parameters from the BMP data */
00339       cinfo->X_density = (UINT16) (biXPelsPerMeter/100); /* 100 cm per meter */
00340       cinfo->Y_density = (UINT16) (biYPelsPerMeter/100);
00341       cinfo->density_unit = 2;     /* dots/cm */
00342     }
00343     break;
00344   default:
00345     ERREXIT(cinfo, JERR_BMP_BADHEADER);
00346     break;
00347   }
00348 
00349   /* Compute distance to bitmap data --- will adjust for colormap below */
00350   bPad = bfOffBits - (headerSize + 14);
00351 
00352   /* Read the colormap, if any */
00353   if (mapentrysize > 0) {
00354     if (biClrUsed <= 0)
00355       biClrUsed = 256;             /* assume it's 256 */
00356     else if (biClrUsed > 256)
00357       ERREXIT(cinfo, JERR_BMP_BADCMAP);
00358     /* Allocate space to store the colormap */
00359     source->colormap = (*cinfo->mem->alloc_sarray)
00360       ((j_common_ptr) cinfo, JPOOL_IMAGE,
00361        (JDIMENSION) biClrUsed, (JDIMENSION) 3);
00362     /* and read it from the file */
00363     read_colormap(source, (int) biClrUsed, mapentrysize);
00364     /* account for size of colormap */
00365     bPad -= biClrUsed * mapentrysize;
00366   }
00367 
00368   /* Skip any remaining pad bytes */
00369   if (bPad < 0)                    /* incorrect bfOffBits value? */
00370     ERREXIT(cinfo, JERR_BMP_BADHEADER);
00371   while (--bPad >= 0) {
00372     (void) read_byte(source);
00373   }
00374 
00375   /* Compute row width in file, including padding to 4-byte boundary */
00376   if (source->bits_per_pixel == 24)
00377     row_width = (JDIMENSION) (biWidth * 3);
00378   else
00379     row_width = (JDIMENSION) biWidth;
00380   while ((row_width & 3) != 0) row_width++;
00381   source->row_width = row_width;
00382 
00383   /* Allocate space for inversion array, prepare for preload pass */
00384   source->whole_image = (*cinfo->mem->request_virt_sarray)
00385     ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
00386      row_width, (JDIMENSION) biHeight, (JDIMENSION) 1);
00387   source->pub.get_pixel_rows = preload_image;
00388   if (cinfo->progress != NULL) {
00389     cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
00390     progress->total_extra_passes++; /* count file input as separate pass */
00391   }
00392 
00393   /* Allocate one-row buffer for returned data */
00394   source->pub.buffer = (*cinfo->mem->alloc_sarray)
00395     ((j_common_ptr) cinfo, JPOOL_IMAGE,
00396      (JDIMENSION) (biWidth * 3), (JDIMENSION) 1);
00397   source->pub.buffer_height = 1;
00398 
00399   cinfo->in_color_space = JCS_RGB;
00400   cinfo->input_components = 3;
00401   cinfo->data_precision = 8;
00402   cinfo->image_width = (JDIMENSION) biWidth;
00403   cinfo->image_height = (JDIMENSION) biHeight;
00404 }
00405 
00406 
00407 /*
00408  * Finish up at the end of the file.
00409  */
00410 
00411 METHODDEF(void)
00412 finish_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
00413 {
00414   /* no work */
00415 }
00416 
00417 
00418 /*
00419  * The module selection routine for BMP format input.
00420  */
00421 
00422 GLOBAL(cjpeg_source_ptr)
00423 jinit_read_bmp (j_compress_ptr cinfo)
00424 {
00425   bmp_source_ptr source;
00426 
00427   /* Create module interface object */
00428   source = (bmp_source_ptr)
00429       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
00430                               SIZEOF(bmp_source_struct));
00431   source->cinfo = cinfo;    /* make back link for subroutines */
00432   /* Fill in method ptrs, except get_pixel_rows which start_input sets */
00433   source->pub.start_input = start_input_bmp;
00434   source->pub.finish_input = finish_input_bmp;
00435 
00436   return (cjpeg_source_ptr) source;
00437 }
00438 
00439 #endif /* BMP_SUPPORTED */