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df9dbff830820c3e0ab36b3c4a1649c614d7ccc5
mozjpeg/rdtarga.c
DRC e8b40f3c2b Vastly improve 12-bit JPEG integration 
The Gordian knot that 7fec5074f9 attempted
to unravel was caused by the fact that there are several
data-precision-dependent (JSAMPLE-dependent) fields and methods in the
exposed libjpeg API structures, and if you change the exposed libjpeg
API structures, then you have to change the whole API.  If you change
the whole API, then you have to provide a whole new library to support
the new API, and that makes it difficult to support multiple data
precisions in the same application.  (It is not impossible, as example.c
demonstrated, but using data-precision-dependent libjpeg API structures
would have made the cjpeg, djpeg, and jpegtran source code hard to read,
so it made more sense to build, install, and package 12-bit-specific
versions of those applications.)

Unfortunately, the result of that initial integration effort was an
unreadable and unmaintainable mess, which is a problem for a library
that is an ISO/ITU-T reference implementation.  Also, as I dug into the
problem of lossless JPEG support, I realized that 16-bit lossless JPEG
images are a thing, and supporting yet another version of the libjpeg
API just for those images is untenable.

In fact, however, the touch points for JSAMPLE in the exposed libjpeg
API structures are minimal:

  - The colormap and sample_range_limit fields in jpeg_decompress_struct
  - The alloc_sarray() and access_virt_sarray() methods in
    jpeg_memory_mgr
  - jpeg_write_scanlines() and jpeg_write_raw_data()
  - jpeg_read_scanlines() and jpeg_read_raw_data()
  - jpeg_skip_scanlines() and jpeg_crop_scanline()
    (This is subtle, but both of those functions use JSAMPLE-dependent
    opaque structures behind the scenes.)

It is much more readable and maintainable to provide 12-bit-specific
versions of those six top-level API functions and to document that the
aforementioned methods and fields must be type-cast when using 12-bit
samples.  Since that eliminates the need to provide a 12-bit-specific
version of the exposed libjpeg API structures, we can:

  - Compile only the precision-dependent libjpeg modules (the
    coefficient buffer controllers, the colorspace converters, the
    DCT/IDCT managers, the main buffer controllers, the preprocessing
    and postprocessing controller, the downsampler and upsamplers, the
    quantizers, the integer DCT methods, and the IDCT methods) for
    multiple data precisions.
  - Introduce 12-bit-specific methods into the various internal
    structures defined in jpegint.h.
  - Create precision-independent data type, macro, method, field, and
    function names that are prefixed by an underscore, and use an
    internal header to convert those into precision-dependent data
    type, macro, method, field, and function names, based on the value
    of BITS_IN_JSAMPLE, when compiling the precision-dependent libjpeg
    modules.
  - Expose precision-dependent jinit*() functions for each of the
    precision-dependent libjpeg modules.
  - Abstract the precision-dependent libjpeg modules by calling the
    appropriate precision-dependent jinit*() function, based on the
    value of cinfo->data_precision, from top-level libjpeg API
    functions.
2022-11-04 12:30:33 -05:00

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/*
* rdtarga.c
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1991-1996, Thomas G. Lane.
* Modified 2017 by Guido Vollbeding.
* libjpeg-turbo Modifications:
* Copyright (C) 2018, 2021-2022, D. R. Commander.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
*
* This file contains routines to read input images in Targa format.
*
* 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 Targa format).
*
* Based on code contributed by Lee Daniel Crocker.
*/
#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
#ifdef TARGA_SUPPORTED
/* Macros to deal with unsigned chars as efficiently as compiler allows */
typedef unsigned char U_CHAR;
#define UCH(x) ((int)(x))
#define ReadOK(file, buffer, len) \
(fread(buffer, 1, len, file) == ((size_t)(len)))
/* Private version of data source object */
typedef struct _tga_source_struct *tga_source_ptr;
typedef struct _tga_source_struct {
struct cjpeg_source_struct pub; /* public fields */
j_compress_ptr cinfo; /* back link saves passing separate parm */
JSAMPARRAY colormap; /* Targa colormap (converted to my format) */
jvirt_sarray_ptr whole_image; /* Needed if funny input row order */
JDIMENSION current_row; /* Current logical row number to read */
/* Pointer to routine to extract next Targa pixel from input file */
void (*read_pixel) (tga_source_ptr sinfo);
/* Result of read_pixel is delivered here: */
U_CHAR tga_pixel[4];
int pixel_size; /* Bytes per Targa pixel (1 to 4) */
int cmap_length; /* colormap length */
/* State info for reading RLE-coded pixels; both counts must be init to 0 */
int block_count; /* # of pixels remaining in RLE block */
int dup_pixel_count; /* # of times to duplicate previous pixel */
/* This saves the correct pixel-row-expansion method for preload_image */
JDIMENSION (*get_pixel_rows) (j_compress_ptr cinfo, cjpeg_source_ptr sinfo);
} tga_source_struct;
/* For expanding 5-bit pixel values to 8-bit with best rounding */
static const UINT8 c5to8bits[32] = {
0, 8, 16, 25, 33, 41, 49, 58,
66, 74, 82, 90, 99, 107, 115, 123,
132, 140, 148, 156, 165, 173, 181, 189,
197, 206, 214, 222, 230, 239, 247, 255
};
LOCAL(int)
read_byte(tga_source_ptr sinfo)
/* Read next byte from Targa 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(tga_source_ptr sinfo, int cmaplen, int mapentrysize)
/* Read the colormap from a Targa file */
{
int i;
/* Presently only handles 24-bit BGR format */
if (mapentrysize != 24)
ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);
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);
}
}
/*
* read_pixel methods: get a single pixel from Targa file into tga_pixel[]
*/
METHODDEF(void)
read_non_rle_pixel(tga_source_ptr sinfo)
/* Read one Targa pixel from the input file; no RLE expansion */
{
register int i;
for (i = 0; i < sinfo->pixel_size; i++) {
sinfo->tga_pixel[i] = (U_CHAR)read_byte(sinfo);
}
}
METHODDEF(void)
read_rle_pixel(tga_source_ptr sinfo)
/* Read one Targa pixel from the input file, expanding RLE data as needed */
{
register int i;
/* Duplicate previously read pixel? */
if (sinfo->dup_pixel_count > 0) {
sinfo->dup_pixel_count--;
return;
}
/* Time to read RLE block header? */
if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
i = read_byte(sinfo);
if (i & 0x80) { /* Start of duplicate-pixel block? */
sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
sinfo->block_count = 0; /* then read new block header */
} else {
sinfo->block_count = i & 0x7F; /* number of pixels after this one */
}
}
/* Read next pixel */
for (i = 0; i < sinfo->pixel_size; i++) {
sinfo->tga_pixel[i] = (U_CHAR)read_byte(sinfo);
}
}
/*
* Read one row of pixels.
*
* We provide several different versions depending on input file format.
*/
METHODDEF(JDIMENSION)
get_8bit_gray_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
/* This version is for reading 8-bit grayscale pixels */
{
tga_source_ptr source = (tga_source_ptr)sinfo;
register JSAMPROW ptr;
register JDIMENSION col;
ptr = source->pub.buffer[0];
for (col = cinfo->image_width; col > 0; col--) {
(*source->read_pixel) (source); /* Load next pixel into tga_pixel */
*ptr++ = (JSAMPLE)UCH(source->tga_pixel[0]);
}
return 1;
}
METHODDEF(JDIMENSION)
get_8bit_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
/* This version is for reading 8-bit colormap indexes */
{
tga_source_ptr source = (tga_source_ptr)sinfo;
register int t;
register JSAMPROW ptr;
register JDIMENSION col;
register JSAMPARRAY colormap = source->colormap;
int cmaplen = source->cmap_length;
ptr = source->pub.buffer[0];
for (col = cinfo->image_width; col > 0; col--) {
(*source->read_pixel) (source); /* Load next pixel into tga_pixel */
t = UCH(source->tga_pixel[0]);
if (t >= cmaplen)
ERREXIT(cinfo, JERR_TGA_BADPARMS);
*ptr++ = colormap[0][t];
*ptr++ = colormap[1][t];
*ptr++ = colormap[2][t];
}
return 1;
}
METHODDEF(JDIMENSION)
get_16bit_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
/* This version is for reading 16-bit pixels */
{
tga_source_ptr source = (tga_source_ptr)sinfo;
register int t;
register JSAMPROW ptr;
register JDIMENSION col;
ptr = source->pub.buffer[0];
for (col = cinfo->image_width; col > 0; col--) {
(*source->read_pixel) (source); /* Load next pixel into tga_pixel */
t = UCH(source->tga_pixel[0]);
t += UCH(source->tga_pixel[1]) << 8;
/* We expand 5 bit data to 8 bit sample width.
* The format of the 16-bit (LSB first) input word is
* xRRRRRGGGGGBBBBB
*/
ptr[2] = (JSAMPLE)c5to8bits[t & 0x1F];
t >>= 5;
ptr[1] = (JSAMPLE)c5to8bits[t & 0x1F];
t >>= 5;
ptr[0] = (JSAMPLE)c5to8bits[t & 0x1F];
ptr += 3;
}
return 1;
}
METHODDEF(JDIMENSION)
get_24bit_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
/* This version is for reading 24-bit pixels */
{
tga_source_ptr source = (tga_source_ptr)sinfo;
register JSAMPROW ptr;
register JDIMENSION col;
ptr = source->pub.buffer[0];
for (col = cinfo->image_width; col > 0; col--) {
(*source->read_pixel) (source); /* Load next pixel into tga_pixel */
*ptr++ = (JSAMPLE)UCH(source->tga_pixel[2]); /* change BGR to RGB order */
*ptr++ = (JSAMPLE)UCH(source->tga_pixel[1]);
*ptr++ = (JSAMPLE)UCH(source->tga_pixel[0]);
}
return 1;
}
/*
* Targa also defines a 32-bit pixel format with order B,G,R,A.
* We presently ignore the attribute byte, so the code for reading
* these pixels is identical to the 24-bit routine above.
* This works because the actual pixel length is only known to read_pixel.
*/
#define get_32bit_row get_24bit_row
/*
* This method is for re-reading the input data in standard top-down
* row order. The entire image has already been read into whole_image
* with proper conversion of pixel format, but it's in a funny row order.
*/
METHODDEF(JDIMENSION)
get_memory_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
{
tga_source_ptr source = (tga_source_ptr)sinfo;
JDIMENSION source_row;
/* Compute row of source that maps to current_row of normal order */
/* For now, assume image is bottom-up and not interlaced. */
/* NEEDS WORK to support interlaced images! */
source_row = cinfo->image_height - source->current_row - 1;
/* Fetch that row from virtual array */
source->pub.buffer = (*cinfo->mem->access_virt_sarray)
((j_common_ptr)cinfo, source->whole_image,
source_row, (JDIMENSION)1, FALSE);
source->current_row++;
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_memory_row on subsequent calls.
*/
METHODDEF(JDIMENSION)
preload_image(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
{
tga_source_ptr source = (tga_source_ptr)sinfo;
JDIMENSION row;
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);
}
source->pub.buffer = (*cinfo->mem->access_virt_sarray)
((j_common_ptr)cinfo, source->whole_image, row, (JDIMENSION)1, TRUE);
(*source->get_pixel_rows) (cinfo, sinfo);
}
if (progress != NULL)
progress->completed_extra_passes++;
/* Set up to read from the virtual array in unscrambled order */
source->pub.get_pixel_rows = get_memory_row;
source->current_row = 0;
/* And read the first row */
return get_memory_row(cinfo, sinfo);
}
/*
* Read the file header; return image size and component count.
*/
METHODDEF(void)
start_input_tga(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
{
tga_source_ptr source = (tga_source_ptr)sinfo;
U_CHAR targaheader[18];
int idlen, cmaptype, subtype, flags, interlace_type, components;
unsigned int width, height, maplen;
boolean is_bottom_up;
#define GET_2B(offset) \
((unsigned int)UCH(targaheader[offset]) + \
(((unsigned int)UCH(targaheader[offset + 1])) << 8))
if (!ReadOK(source->pub.input_file, targaheader, 18))
ERREXIT(cinfo, JERR_INPUT_EOF);
/* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
if (targaheader[16] == 15)
targaheader[16] = 16;
idlen = UCH(targaheader[0]);
cmaptype = UCH(targaheader[1]);
subtype = UCH(targaheader[2]);
maplen = GET_2B(5);
width = GET_2B(12);
height = GET_2B(14);
source->pixel_size = UCH(targaheader[16]) >> 3;
flags = UCH(targaheader[17]); /* Image Descriptor byte */
is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */
interlace_type = flags >> 6; /* bits 6/7 are interlace code */
if (cmaptype > 1 || /* cmaptype must be 0 or 1 */
source->pixel_size < 1 || source->pixel_size > 4 ||
(UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */
interlace_type != 0 || /* currently don't allow interlaced image */
width == 0 || height == 0) /* image width/height must be non-zero */
ERREXIT(cinfo, JERR_TGA_BADPARMS);
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
if (sinfo->max_pixels &&
(unsigned long long)width * height > sinfo->max_pixels)
ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
#endif
if (subtype > 8) {
/* It's an RLE-coded file */
source->read_pixel = read_rle_pixel;
source->block_count = source->dup_pixel_count = 0;
subtype -= 8;
} else {
/* Non-RLE file */
source->read_pixel = read_non_rle_pixel;
}
/* Now should have subtype 1, 2, or 3 */
components = 3; /* until proven different */
cinfo->in_color_space = JCS_RGB;
switch (subtype) {
case 1: /* Colormapped image */
if (source->pixel_size == 1 && cmaptype == 1)
source->get_pixel_rows = get_8bit_row;
else
ERREXIT(cinfo, JERR_TGA_BADPARMS);
TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
break;
case 2: /* RGB image */
switch (source->pixel_size) {
case 2:
source->get_pixel_rows = get_16bit_row;
break;
case 3:
source->get_pixel_rows = get_24bit_row;
break;
case 4:
source->get_pixel_rows = get_32bit_row;
break;
default:
ERREXIT(cinfo, JERR_TGA_BADPARMS);
break;
}
TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
break;
case 3: /* Grayscale image */
components = 1;
cinfo->in_color_space = JCS_GRAYSCALE;
if (source->pixel_size == 1)
source->get_pixel_rows = get_8bit_gray_row;
else
ERREXIT(cinfo, JERR_TGA_BADPARMS);
TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
break;
default:
ERREXIT(cinfo, JERR_TGA_BADPARMS);
break;
}
if (is_bottom_up) {
/* Create a virtual array to buffer the upside-down image. */
source->whole_image = (*cinfo->mem->request_virt_sarray)
((j_common_ptr)cinfo, JPOOL_IMAGE, FALSE,
(JDIMENSION)width * components, (JDIMENSION)height, (JDIMENSION)1);
if (cinfo->progress != NULL) {
cd_progress_ptr progress = (cd_progress_ptr)cinfo->progress;
progress->total_extra_passes++; /* count file input as separate pass */
}
/* source->pub.buffer will point to the virtual array. */
source->pub.buffer_height = 1; /* in case anyone looks at it */
source->pub.get_pixel_rows = preload_image;
} else {
/* Don't need a virtual array, but do need a one-row input buffer. */
source->whole_image = NULL;
source->pub.buffer = (*cinfo->mem->alloc_sarray)
((j_common_ptr)cinfo, JPOOL_IMAGE,
(JDIMENSION)width * components, (JDIMENSION)1);
source->pub.buffer_height = 1;
source->pub.get_pixel_rows = source->get_pixel_rows;
}
while (idlen--) /* Throw away ID field */
(void)read_byte(source);
if (maplen > 0) {
if (maplen > 256 || GET_2B(3) != 0)
ERREXIT(cinfo, JERR_TGA_BADCMAP);
/* Allocate space to store the colormap */
source->colormap = (*cinfo->mem->alloc_sarray)
((j_common_ptr)cinfo, JPOOL_IMAGE, (JDIMENSION)maplen, (JDIMENSION)3);
source->cmap_length = (int)maplen;
/* and read it from the file */
read_colormap(source, (int)maplen, UCH(targaheader[7]));
} else {
if (cmaptype) /* but you promised a cmap! */
ERREXIT(cinfo, JERR_TGA_BADPARMS);
source->colormap = NULL;
source->cmap_length = 0;
}
cinfo->input_components = components;
cinfo->data_precision = 8;
cinfo->image_width = width;
cinfo->image_height = height;
}
/*
* Finish up at the end of the file.
*/
METHODDEF(void)
finish_input_tga(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
{
/* no work */
}
/*
* The module selection routine for Targa format input.
*/
GLOBAL(cjpeg_source_ptr)
jinit_read_targa(j_compress_ptr cinfo)
{
tga_source_ptr source;
if (cinfo->data_precision != 8)
ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
/* Create module interface object */
source = (tga_source_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
sizeof(tga_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_tga;
source->pub.finish_input = finish_input_tga;
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
source->pub.max_pixels = 0;
#endif
return (cjpeg_source_ptr)source;
}
#endif /* TARGA_SUPPORTED */
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