ref: c57c8919e303aaad512a5e603f60d4be22d6afea
dir: /sys/src/cmd/gs/jpeg/rdbmp.c/
/*
* rdbmp.c
*
* Copyright (C) 1994-1996, 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 */