rdbmp.c - third_party/libjpeg-turbo - Git at Google

 /*
  * rdbmp.c
  *
  * Copyright (C) 1994-1995, Thomas G. Lane.
  * This file is part of the Independent JPEG Group's software.
  * For conditions of distribution and use, see the accompanying README file.
  *
  * This file contains routines to read input images in Microsoft "BMP"
  * format (MS Windows 3.x, OS/2 1.x, and OS/2 2.x flavors).
  * Currently, only 8-bit and 24-bit images are supported, not 1-bit or
  * 4-bit (feeding such low-depth images into JPEG would be silly anyway).
  * Also, we don't support RLE-compressed files.
  *
  * These routines may need modification for non-Unix environments or
  * specialized applications.  As they stand, they assume input from
  * an ordinary stdio stream.  They further assume that reading begins
  * at the start of the file; start_input may need work if the
  * user interface has already read some data (e.g., to determine that
  * the file is indeed BMP format).
  *
  * This code contributed by James Arthur Boucher.
  */

 #include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */

 #ifdef BMP_SUPPORTED


 /* Macros to deal with unsigned chars as efficiently as compiler allows */

 #ifdef HAVE_UNSIGNED_CHAR
 typedef unsigned char U_CHAR;
 #define UCH(x)	((int) (x))
 #else /* !HAVE_UNSIGNED_CHAR */
 #ifdef CHAR_IS_UNSIGNED
 typedef char U_CHAR;
 #define UCH(x)	((int) (x))
 #else
 typedef char U_CHAR;
 #define UCH(x)	((int) (x) & 0xFF)
 #endif
 #endif /* HAVE_UNSIGNED_CHAR */


 #define	ReadOK(file,buffer,len)	(JFREAD(file,buffer,len) == ((size_t) (len)))


 /* Private version of data source object */

 typedef struct _bmp_source_struct * bmp_source_ptr;

 typedef struct _bmp_source_struct {
   struct cjpeg_source_struct pub; /* public fields */

   j_compress_ptr cinfo;		/* back link saves passing separate parm */

   JSAMPARRAY colormap;		/* BMP colormap (converted to my format) */

   jvirt_sarray_ptr whole_image;	/* Needed to reverse row order */
   JDIMENSION source_row;	/* Current source row number */
   JDIMENSION row_width;		/* Physical width of scanlines in file */

   int bits_per_pixel;		/* remembers 8- or 24-bit format */
 } bmp_source_struct;


 LOCAL int
 read_byte (bmp_source_ptr sinfo)
 /* Read next byte from BMP file */
 {
   register FILE *infile = sinfo->pub.input_file;
   register int c;

   if ((c = getc(infile)) == EOF)
     ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
   return c;
 }


 LOCAL void
 read_colormap (bmp_source_ptr sinfo, int cmaplen, int mapentrysize)
 /* Read the colormap from a BMP file */
 {
   int i;

   switch (mapentrysize) {
   case 3:
     /* BGR format (occurs in OS/2 files) */
     for (i = 0; i < cmaplen; i++) {
       sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
       sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
       sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
     }
     break;
   case 4:
     /* BGR0 format (occurs in MS Windows files) */
     for (i = 0; i < cmaplen; i++) {
       sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
       sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
       sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
       (void) read_byte(sinfo);
     }
     break;
   default:
     ERREXIT(sinfo->cinfo, JERR_BMP_BADCMAP);
     break;
   }
 }


 /*
  * Read one row of pixels.
  * The image has been read into the whole_image array, but is otherwise
  * unprocessed.  We must read it out in top-to-bottom row order, and if
  * it is an 8-bit image, we must expand colormapped pixels to 24bit format.
  */

 METHODDEF JDIMENSION
 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 /* This version is for reading 8-bit colormap indexes */
 {
   bmp_source_ptr source = (bmp_source_ptr) sinfo;
   register JSAMPARRAY colormap = source->colormap;
   JSAMPARRAY image_ptr;
   register int t;
   register JSAMPROW inptr, outptr;
   register JDIMENSION col;

   /* Fetch next row from virtual array */
   source->source_row--;
   image_ptr = (*cinfo->mem->access_virt_sarray)
     ((j_common_ptr) cinfo, source->whole_image,
      source->source_row, (JDIMENSION) 1, FALSE);

   /* Expand the colormap indexes to real data */
   inptr = image_ptr[0];
   outptr = source->pub.buffer[0];
   for (col = cinfo->image_width; col > 0; col--) {
     t = GETJSAMPLE(*inptr++);
     *outptr++ = colormap[0][t];	/* can omit GETJSAMPLE() safely */
     *outptr++ = colormap[1][t];
     *outptr++ = colormap[2][t];
   }

   return 1;
 }


 METHODDEF JDIMENSION
 get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 /* This version is for reading 24-bit pixels */
 {
   bmp_source_ptr source = (bmp_source_ptr) sinfo;
   JSAMPARRAY image_ptr;
   register JSAMPROW inptr, outptr;
   register JDIMENSION col;

   /* Fetch next row from virtual array */
   source->source_row--;
   image_ptr = (*cinfo->mem->access_virt_sarray)
     ((j_common_ptr) cinfo, source->whole_image,
      source->source_row, (JDIMENSION) 1, FALSE);

   /* Transfer data.  Note source values are in BGR order
    * (even though Microsoft's own documents say the opposite).
    */
   inptr = image_ptr[0];
   outptr = source->pub.buffer[0];
   for (col = cinfo->image_width; col > 0; col--) {
     outptr[2] = *inptr++;	/* can omit GETJSAMPLE() safely */
     outptr[1] = *inptr++;
     outptr[0] = *inptr++;
     outptr += 3;
   }

   return 1;
 }


 /*
  * This method loads the image into whole_image during the first call on
  * get_pixel_rows.  The get_pixel_rows pointer is then adjusted to call
  * get_8bit_row or get_24bit_row on subsequent calls.
  */

 METHODDEF JDIMENSION
 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 {
   bmp_source_ptr source = (bmp_source_ptr) sinfo;
   register FILE *infile = source->pub.input_file;
   register int c;
   register JSAMPROW out_ptr;
   JSAMPARRAY image_ptr;
   JDIMENSION row, col;
   cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;

   /* Read the data into a virtual array in input-file row order. */
   for (row = 0; row < cinfo->image_height; row++) {
     if (progress != NULL) {
       progress->pub.pass_counter = (long) row;
       progress->pub.pass_limit = (long) cinfo->image_height;
       (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
     }
     image_ptr = (*cinfo->mem->access_virt_sarray)
       ((j_common_ptr) cinfo, source->whole_image,
        row, (JDIMENSION) 1, TRUE);
     out_ptr = image_ptr[0];
     for (col = source->row_width; col > 0; col--) {
       /* inline copy of read_byte() for speed */
       if ((c = getc(infile)) == EOF)
 	ERREXIT(cinfo, JERR_INPUT_EOF);
       *out_ptr++ = (JSAMPLE) c;
     }
   }
   if (progress != NULL)
     progress->completed_extra_passes++;

   /* Set up to read from the virtual array in top-to-bottom order */
   switch (source->bits_per_pixel) {
   case 8:
     source->pub.get_pixel_rows = get_8bit_row;
     break;
   case 24:
     source->pub.get_pixel_rows = get_24bit_row;
     break;
   default:
     ERREXIT(cinfo, JERR_BMP_BADDEPTH);
   }
   source->source_row = cinfo->image_height;

   /* And read the first row */
   return (*source->pub.get_pixel_rows) (cinfo, sinfo);
 }


 /*
  * Read the file header; return image size and component count.
  */

 METHODDEF void
 start_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 {
   bmp_source_ptr source = (bmp_source_ptr) sinfo;
   U_CHAR bmpfileheader[14];
   U_CHAR bmpinfoheader[64];
 #define GET_2B(array,offset)  ((unsigned int) UCH(array[offset]) + \
 			       (((unsigned int) UCH(array[offset+1])) << 8))
 #define GET_4B(array,offset)  ((INT32) UCH(array[offset]) + \
 			       (((INT32) UCH(array[offset+1])) << 8) + \
 			       (((INT32) UCH(array[offset+2])) << 16) + \
 			       (((INT32) UCH(array[offset+3])) << 24))
   INT32 bfOffBits;
   INT32 headerSize;
   INT32 biWidth = 0;		/* initialize to avoid compiler warning */
   INT32 biHeight = 0;
   unsigned int biPlanes;
   INT32 biCompression;
   INT32 biXPelsPerMeter,biYPelsPerMeter;
   INT32 biClrUsed = 0;
   int mapentrysize = 0;		/* 0 indicates no colormap */
   INT32 bPad;
   JDIMENSION row_width;

   /* Read and verify the bitmap file header */
   if (! ReadOK(source->pub.input_file, bmpfileheader, 14))
     ERREXIT(cinfo, JERR_INPUT_EOF);
   if (GET_2B(bmpfileheader,0) != 0x4D42) /* 'BM' */
     ERREXIT(cinfo, JERR_BMP_NOT);
   bfOffBits = (INT32) GET_4B(bmpfileheader,10);
   /* We ignore the remaining fileheader fields */

   /* The infoheader might be 12 bytes (OS/2 1.x), 40 bytes (Windows),
    * or 64 bytes (OS/2 2.x).  Check the first 4 bytes to find out which.
    */
   if (! ReadOK(source->pub.input_file, bmpinfoheader, 4))
     ERREXIT(cinfo, JERR_INPUT_EOF);
   headerSize = (INT32) GET_4B(bmpinfoheader,0);
   if (headerSize < 12 || headerSize > 64)
     ERREXIT(cinfo, JERR_BMP_BADHEADER);
   if (! ReadOK(source->pub.input_file, bmpinfoheader+4, headerSize-4))
     ERREXIT(cinfo, JERR_INPUT_EOF);

   switch ((int) headerSize) {
   case 12:
     /* Decode OS/2 1.x header (Microsoft calls this a BITMAPCOREHEADER) */
     biWidth = (INT32) GET_2B(bmpinfoheader,4);
     biHeight = (INT32) GET_2B(bmpinfoheader,6);
     biPlanes = GET_2B(bmpinfoheader,8);
     source->bits_per_pixel = (int) GET_2B(bmpinfoheader,10);

     switch (source->bits_per_pixel) {
     case 8:			/* colormapped image */
       mapentrysize = 3;		/* OS/2 uses RGBTRIPLE colormap */
       TRACEMS2(cinfo, 1, JTRC_BMP_OS2_MAPPED, (int) biWidth, (int) biHeight);
       break;
     case 24:			/* RGB image */
       TRACEMS2(cinfo, 1, JTRC_BMP_OS2, (int) biWidth, (int) biHeight);
       break;
     default:
       ERREXIT(cinfo, JERR_BMP_BADDEPTH);
       break;
     }
     if (biPlanes != 1)
       ERREXIT(cinfo, JERR_BMP_BADPLANES);
     break;
   case 40:
   case 64:
     /* Decode Windows 3.x header (Microsoft calls this a BITMAPINFOHEADER) */
     /* or OS/2 2.x header, which has additional fields that we ignore */
     biWidth = GET_4B(bmpinfoheader,4);
     biHeight = GET_4B(bmpinfoheader,8);
     biPlanes = GET_2B(bmpinfoheader,12);
     source->bits_per_pixel = (int) GET_2B(bmpinfoheader,14);
     biCompression = GET_4B(bmpinfoheader,16);
     biXPelsPerMeter = GET_4B(bmpinfoheader,24);
     biYPelsPerMeter = GET_4B(bmpinfoheader,28);
     biClrUsed = GET_4B(bmpinfoheader,32);
     /* biSizeImage, biClrImportant fields are ignored */

     switch (source->bits_per_pixel) {
     case 8:			/* colormapped image */
       mapentrysize = 4;		/* Windows uses RGBQUAD colormap */
       TRACEMS2(cinfo, 1, JTRC_BMP_MAPPED, (int) biWidth, (int) biHeight);
       break;
     case 24:			/* RGB image */
       TRACEMS2(cinfo, 1, JTRC_BMP, (int) biWidth, (int) biHeight);
       break;
     default:
       ERREXIT(cinfo, JERR_BMP_BADDEPTH);
       break;
     }
     if (biPlanes != 1)
       ERREXIT(cinfo, JERR_BMP_BADPLANES);
     if (biCompression != 0)
       ERREXIT(cinfo, JERR_BMP_COMPRESSED);

     if (biXPelsPerMeter > 0 && biYPelsPerMeter > 0) {
       /* Set JFIF density parameters from the BMP data */
       cinfo->X_density = (UINT16) (biXPelsPerMeter/100); /* 100 cm per meter */
       cinfo->Y_density = (UINT16) (biYPelsPerMeter/100);
       cinfo->density_unit = 2;	/* dots/cm */
     }
     break;
   default:
     ERREXIT(cinfo, JERR_BMP_BADHEADER);
     break;
   }

   /* Compute distance to bitmap data --- will adjust for colormap below */
   bPad = bfOffBits - (headerSize + 14);

   /* Read the colormap, if any */
   if (mapentrysize > 0) {
     if (biClrUsed <= 0)
       biClrUsed = 256;		/* assume it's 256 */
     else if (biClrUsed > 256)
       ERREXIT(cinfo, JERR_BMP_BADCMAP);
     /* Allocate space to store the colormap */
     source->colormap = (*cinfo->mem->alloc_sarray)
       ((j_common_ptr) cinfo, JPOOL_IMAGE,
        (JDIMENSION) biClrUsed, (JDIMENSION) 3);
     /* and read it from the file */
     read_colormap(source, (int) biClrUsed, mapentrysize);
     /* account for size of colormap */
     bPad -= biClrUsed * mapentrysize;
   }

   /* Skip any remaining pad bytes */
   if (bPad < 0)			/* incorrect bfOffBits value? */
     ERREXIT(cinfo, JERR_BMP_BADHEADER);
   while (--bPad >= 0) {
     (void) read_byte(source);
   }

   /* Compute row width in file, including padding to 4-byte boundary */
   if (source->bits_per_pixel == 24)
     row_width = (JDIMENSION) (biWidth * 3);
   else
     row_width = (JDIMENSION) biWidth;
   while ((row_width & 3) != 0) row_width++;
   source->row_width = row_width;

   /* Allocate space for inversion array, prepare for preload pass */
   source->whole_image = (*cinfo->mem->request_virt_sarray)
     ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
      row_width, (JDIMENSION) biHeight, (JDIMENSION) 1);
   source->pub.get_pixel_rows = preload_image;
   if (cinfo->progress != NULL) {
     cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
     progress->total_extra_passes++; /* count file input as separate pass */
   }

   /* Allocate one-row buffer for returned data */
   source->pub.buffer = (*cinfo->mem->alloc_sarray)
     ((j_common_ptr) cinfo, JPOOL_IMAGE,
      (JDIMENSION) (biWidth * 3), (JDIMENSION) 1);
   source->pub.buffer_height = 1;

   cinfo->in_color_space = JCS_RGB;
   cinfo->input_components = 3;
   cinfo->data_precision = 8;
   cinfo->image_width = (JDIMENSION) biWidth;
   cinfo->image_height = (JDIMENSION) biHeight;
 }


 /*
  * Finish up at the end of the file.
  */

 METHODDEF void
 finish_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 {
   /* no work */
 }


 /*
  * The module selection routine for BMP format input.
  */

 GLOBAL cjpeg_source_ptr
 jinit_read_bmp (j_compress_ptr cinfo)
 {
   bmp_source_ptr source;

   /* Create module interface object */
   source = (bmp_source_ptr)
       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				  SIZEOF(bmp_source_struct));
   source->cinfo = cinfo;	/* make back link for subroutines */
   /* Fill in method ptrs, except get_pixel_rows which start_input sets */
   source->pub.start_input = start_input_bmp;
   source->pub.finish_input = finish_input_bmp;

   return (cjpeg_source_ptr) source;
 }

 #endif /* BMP_SUPPORTED */
	/*
	* rdbmp.c
	*
	* Copyright (C) 1994-1995, Thomas G. Lane.
	* This file is part of the Independent JPEG Group's software.
	* For conditions of distribution and use, see the accompanying README file.
	*
	* This file contains routines to read input images in Microsoft "BMP"
	* format (MS Windows 3.x, OS/2 1.x, and OS/2 2.x flavors).
	* Currently, only 8-bit and 24-bit images are supported, not 1-bit or
	* 4-bit (feeding such low-depth images into JPEG would be silly anyway).
	* Also, we don't support RLE-compressed files.
	*
	* These routines may need modification for non-Unix environments or
	* specialized applications. As they stand, they assume input from
	* an ordinary stdio stream. They further assume that reading begins
	* at the start of the file; start_input may need work if the
	* user interface has already read some data (e.g., to determine that
	* the file is indeed BMP format).
	*
	* This code contributed by James Arthur Boucher.
	*/

	#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */

	#ifdef BMP_SUPPORTED


	/* Macros to deal with unsigned chars as efficiently as compiler allows */

	#ifdef HAVE_UNSIGNED_CHAR
	typedef unsigned char U_CHAR;
	#define UCH(x) ((int) (x))
	#else /* !HAVE_UNSIGNED_CHAR */
	#ifdef CHAR_IS_UNSIGNED
	typedef char U_CHAR;
	#define UCH(x) ((int) (x))
	#else
	typedef char U_CHAR;
	#define UCH(x) ((int) (x) & 0xFF)
	#endif
	#endif /* HAVE_UNSIGNED_CHAR */


	#define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))


	/* Private version of data source object */

	typedef struct _bmp_source_struct * bmp_source_ptr;

	typedef struct _bmp_source_struct {
	struct cjpeg_source_struct pub; /* public fields */

	j_compress_ptr cinfo; /* back link saves passing separate parm */

	JSAMPARRAY colormap; /* BMP colormap (converted to my format) */

	jvirt_sarray_ptr whole_image; /* Needed to reverse row order */
	JDIMENSION source_row; /* Current source row number */
	JDIMENSION row_width; /* Physical width of scanlines in file */

	int bits_per_pixel; /* remembers 8- or 24-bit format */
	} bmp_source_struct;


	LOCAL int
	read_byte (bmp_source_ptr sinfo)
	/* Read next byte from BMP file */
	{
	register FILE *infile = sinfo->pub.input_file;
	register int c;

	if ((c = getc(infile)) == EOF)
	ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
	return c;
	}


	LOCAL void
	read_colormap (bmp_source_ptr sinfo, int cmaplen, int mapentrysize)
	/* Read the colormap from a BMP file */
	{
	int i;

	switch (mapentrysize) {
	case 3:
	/* BGR format (occurs in OS/2 files) */
	for (i = 0; i < cmaplen; i++) {
	sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
	sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
	sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
	}
	break;
	case 4:
	/* BGR0 format (occurs in MS Windows files) */
	for (i = 0; i < cmaplen; i++) {
	sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
	sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
	sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
	(void) read_byte(sinfo);
	}
	break;
	default:
	ERREXIT(sinfo->cinfo, JERR_BMP_BADCMAP);
	break;
	}
	}


	/*
	* Read one row of pixels.
	* The image has been read into the whole_image array, but is otherwise
	* unprocessed. We must read it out in top-to-bottom row order, and if
	* it is an 8-bit image, we must expand colormapped pixels to 24bit format.
	*/

	METHODDEF JDIMENSION
	get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
	/* This version is for reading 8-bit colormap indexes */
	{
	bmp_source_ptr source = (bmp_source_ptr) sinfo;
	register JSAMPARRAY colormap = source->colormap;
	JSAMPARRAY image_ptr;
	register int t;
	register JSAMPROW inptr, outptr;
	register JDIMENSION col;

	/* Fetch next row from virtual array */
	source->source_row--;
	image_ptr = (*cinfo->mem->access_virt_sarray)
	((j_common_ptr) cinfo, source->whole_image,
	source->source_row, (JDIMENSION) 1, FALSE);

	/* Expand the colormap indexes to real data */
	inptr = image_ptr[0];
	outptr = source->pub.buffer[0];
	for (col = cinfo->image_width; col > 0; col--) {
	t = GETJSAMPLE(*inptr++);
	outptr++ = colormap[0][t]; / can omit GETJSAMPLE() safely */
	*outptr++ = colormap[1][t];
	*outptr++ = colormap[2][t];
	}

	return 1;
	}


	METHODDEF JDIMENSION
	get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
	/* This version is for reading 24-bit pixels */
	{
	bmp_source_ptr source = (bmp_source_ptr) sinfo;
	JSAMPARRAY image_ptr;
	register JSAMPROW inptr, outptr;
	register JDIMENSION col;

	/* Fetch next row from virtual array */
	source->source_row--;
	image_ptr = (*cinfo->mem->access_virt_sarray)
	((j_common_ptr) cinfo, source->whole_image,
	source->source_row, (JDIMENSION) 1, FALSE);

	/* Transfer data. Note source values are in BGR order
	* (even though Microsoft's own documents say the opposite).
	*/
	inptr = image_ptr[0];
	outptr = source->pub.buffer[0];
	for (col = cinfo->image_width; col > 0; col--) {
	outptr[2] = inptr++; / can omit GETJSAMPLE() safely */
	outptr[1] = *inptr++;
	outptr[0] = *inptr++;
	outptr += 3;
	}

	return 1;
	}


	/*
	* This method loads the image into whole_image during the first call on
	* get_pixel_rows. The get_pixel_rows pointer is then adjusted to call
	* get_8bit_row or get_24bit_row on subsequent calls.
	*/

	METHODDEF JDIMENSION
	preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
	{
	bmp_source_ptr source = (bmp_source_ptr) sinfo;
	register FILE *infile = source->pub.input_file;
	register int c;
	register JSAMPROW out_ptr;
	JSAMPARRAY image_ptr;
	JDIMENSION row, col;
	cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;

	/* Read the data into a virtual array in input-file row order. */
	for (row = 0; row < cinfo->image_height; row++) {
	if (progress != NULL) {
	progress->pub.pass_counter = (long) row;
	progress->pub.pass_limit = (long) cinfo->image_height;
	(*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
	}
	image_ptr = (*cinfo->mem->access_virt_sarray)
	((j_common_ptr) cinfo, source->whole_image,
	row, (JDIMENSION) 1, TRUE);
	out_ptr = image_ptr[0];
	for (col = source->row_width; col > 0; col--) {
	/* inline copy of read_byte() for speed */
	if ((c = getc(infile)) == EOF)
	ERREXIT(cinfo, JERR_INPUT_EOF);
	*out_ptr++ = (JSAMPLE) c;
	}
	}
	if (progress != NULL)
	progress->completed_extra_passes++;

	/* Set up to read from the virtual array in top-to-bottom order */
	switch (source->bits_per_pixel) {
	case 8:
	source->pub.get_pixel_rows = get_8bit_row;
	break;
	case 24:
	source->pub.get_pixel_rows = get_24bit_row;
	break;
	default:
	ERREXIT(cinfo, JERR_BMP_BADDEPTH);
	}
	source->source_row = cinfo->image_height;

	/* And read the first row */
	return (*source->pub.get_pixel_rows) (cinfo, sinfo);
	}


	/*
	* Read the file header; return image size and component count.
	*/

	METHODDEF void
	start_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
	{
	bmp_source_ptr source = (bmp_source_ptr) sinfo;
	U_CHAR bmpfileheader[14];
	U_CHAR bmpinfoheader[64];
	#define GET_2B(array,offset) ((unsigned int) UCH(array[offset]) + \
	(((unsigned int) UCH(array[offset+1])) << 8))
	#define GET_4B(array,offset) ((INT32) UCH(array[offset]) + \
	(((INT32) UCH(array[offset+1])) << 8) + \
	(((INT32) UCH(array[offset+2])) << 16) + \
	(((INT32) UCH(array[offset+3])) << 24))
	INT32 bfOffBits;
	INT32 headerSize;
	INT32 biWidth = 0; /* initialize to avoid compiler warning */
	INT32 biHeight = 0;
	unsigned int biPlanes;
	INT32 biCompression;
	INT32 biXPelsPerMeter,biYPelsPerMeter;
	INT32 biClrUsed = 0;
	int mapentrysize = 0; /* 0 indicates no colormap */
	INT32 bPad;
	JDIMENSION row_width;

	/* Read and verify the bitmap file header */
	if (! ReadOK(source->pub.input_file, bmpfileheader, 14))
	ERREXIT(cinfo, JERR_INPUT_EOF);
	if (GET_2B(bmpfileheader,0) != 0x4D42) /* 'BM' */
	ERREXIT(cinfo, JERR_BMP_NOT);
	bfOffBits = (INT32) GET_4B(bmpfileheader,10);
	/* We ignore the remaining fileheader fields */

	/* The infoheader might be 12 bytes (OS/2 1.x), 40 bytes (Windows),
	* or 64 bytes (OS/2 2.x). Check the first 4 bytes to find out which.
	*/
	if (! ReadOK(source->pub.input_file, bmpinfoheader, 4))
	ERREXIT(cinfo, JERR_INPUT_EOF);
	headerSize = (INT32) GET_4B(bmpinfoheader,0);
	if (headerSize < 12 \|\| headerSize > 64)
	ERREXIT(cinfo, JERR_BMP_BADHEADER);
	if (! ReadOK(source->pub.input_file, bmpinfoheader+4, headerSize-4))
	ERREXIT(cinfo, JERR_INPUT_EOF);

	switch ((int) headerSize) {
	case 12:
	/* Decode OS/2 1.x header (Microsoft calls this a BITMAPCOREHEADER) */
	biWidth = (INT32) GET_2B(bmpinfoheader,4);
	biHeight = (INT32) GET_2B(bmpinfoheader,6);
	biPlanes = GET_2B(bmpinfoheader,8);
	source->bits_per_pixel = (int) GET_2B(bmpinfoheader,10);

	switch (source->bits_per_pixel) {
	case 8: /* colormapped image */
	mapentrysize = 3; /* OS/2 uses RGBTRIPLE colormap */
	TRACEMS2(cinfo, 1, JTRC_BMP_OS2_MAPPED, (int) biWidth, (int) biHeight);
	break;
	case 24: /* RGB image */
	TRACEMS2(cinfo, 1, JTRC_BMP_OS2, (int) biWidth, (int) biHeight);
	break;
	default:
	ERREXIT(cinfo, JERR_BMP_BADDEPTH);
	break;
	}
	if (biPlanes != 1)
	ERREXIT(cinfo, JERR_BMP_BADPLANES);
	break;
	case 40:
	case 64:
	/* Decode Windows 3.x header (Microsoft calls this a BITMAPINFOHEADER) */
	/* or OS/2 2.x header, which has additional fields that we ignore */
	biWidth = GET_4B(bmpinfoheader,4);
	biHeight = GET_4B(bmpinfoheader,8);
	biPlanes = GET_2B(bmpinfoheader,12);
	source->bits_per_pixel = (int) GET_2B(bmpinfoheader,14);
	biCompression = GET_4B(bmpinfoheader,16);
	biXPelsPerMeter = GET_4B(bmpinfoheader,24);
	biYPelsPerMeter = GET_4B(bmpinfoheader,28);
	biClrUsed = GET_4B(bmpinfoheader,32);
	/* biSizeImage, biClrImportant fields are ignored */

	switch (source->bits_per_pixel) {
	case 8: /* colormapped image */
	mapentrysize = 4; /* Windows uses RGBQUAD colormap */
	TRACEMS2(cinfo, 1, JTRC_BMP_MAPPED, (int) biWidth, (int) biHeight);
	break;
	case 24: /* RGB image */
	TRACEMS2(cinfo, 1, JTRC_BMP, (int) biWidth, (int) biHeight);
	break;
	default:
	ERREXIT(cinfo, JERR_BMP_BADDEPTH);
	break;
	}
	if (biPlanes != 1)
	ERREXIT(cinfo, JERR_BMP_BADPLANES);
	if (biCompression != 0)
	ERREXIT(cinfo, JERR_BMP_COMPRESSED);

	if (biXPelsPerMeter > 0 && biYPelsPerMeter > 0) {
	/* Set JFIF density parameters from the BMP data */
	cinfo->X_density = (UINT16) (biXPelsPerMeter/100); /* 100 cm per meter */
	cinfo->Y_density = (UINT16) (biYPelsPerMeter/100);
	cinfo->density_unit = 2; /* dots/cm */
	}
	break;
	default:
	ERREXIT(cinfo, JERR_BMP_BADHEADER);
	break;
	}

	/* Compute distance to bitmap data --- will adjust for colormap below */
	bPad = bfOffBits - (headerSize + 14);

	/* Read the colormap, if any */
	if (mapentrysize > 0) {
	if (biClrUsed <= 0)
	biClrUsed = 256; /* assume it's 256 */
	else if (biClrUsed > 256)
	ERREXIT(cinfo, JERR_BMP_BADCMAP);
	/* Allocate space to store the colormap */
	source->colormap = (*cinfo->mem->alloc_sarray)
	((j_common_ptr) cinfo, JPOOL_IMAGE,
	(JDIMENSION) biClrUsed, (JDIMENSION) 3);
	/* and read it from the file */
	read_colormap(source, (int) biClrUsed, mapentrysize);
	/* account for size of colormap */
	bPad -= biClrUsed * mapentrysize;
	}

	/* Skip any remaining pad bytes */
	if (bPad < 0) /* incorrect bfOffBits value? */
	ERREXIT(cinfo, JERR_BMP_BADHEADER);
	while (--bPad >= 0) {
	(void) read_byte(source);
	}

	/* Compute row width in file, including padding to 4-byte boundary */
	if (source->bits_per_pixel == 24)
	row_width = (JDIMENSION) (biWidth * 3);
	else
	row_width = (JDIMENSION) biWidth;
	while ((row_width & 3) != 0) row_width++;
	source->row_width = row_width;

	/* Allocate space for inversion array, prepare for preload pass */
	source->whole_image = (*cinfo->mem->request_virt_sarray)
	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
	row_width, (JDIMENSION) biHeight, (JDIMENSION) 1);
	source->pub.get_pixel_rows = preload_image;
	if (cinfo->progress != NULL) {
	cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
	progress->total_extra_passes++; /* count file input as separate pass */
	}

	/* Allocate one-row buffer for returned data */
	source->pub.buffer = (*cinfo->mem->alloc_sarray)
	((j_common_ptr) cinfo, JPOOL_IMAGE,
	(JDIMENSION) (biWidth * 3), (JDIMENSION) 1);
	source->pub.buffer_height = 1;

	cinfo->in_color_space = JCS_RGB;
	cinfo->input_components = 3;
	cinfo->data_precision = 8;
	cinfo->image_width = (JDIMENSION) biWidth;
	cinfo->image_height = (JDIMENSION) biHeight;
	}


	/*
	* Finish up at the end of the file.
	*/

	METHODDEF void
	finish_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
	{
	/* no work */
	}


	/*
	* The module selection routine for BMP format input.
	*/

	GLOBAL cjpeg_source_ptr
	jinit_read_bmp (j_compress_ptr cinfo)
	{
	bmp_source_ptr source;

	/* Create module interface object */
	source = (bmp_source_ptr)
	(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
	SIZEOF(bmp_source_struct));
	source->cinfo = cinfo; /* make back link for subroutines */
	/* Fill in method ptrs, except get_pixel_rows which start_input sets */
	source->pub.start_input = start_input_bmp;
	source->pub.finish_input = finish_input_bmp;

	return (cjpeg_source_ptr) source;
	}

	#endif /* BMP_SUPPORTED */