* jdmaster.c
*
* Copyright (C) 1991-1997, Thomas G. Lane.
- * Modified 2002-2011 by Guido Vollbeding.
+ * Modified 2002-2015 by Guido Vollbeding.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
use_merged_upsample (j_decompress_ptr cinfo)
{
#ifdef UPSAMPLE_MERGING_SUPPORTED
- /* Merging is the equivalent of plain box-filter upsampling */
- if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
+ /* Merging is the equivalent of plain box-filter upsampling. */
+ /* The following condition is only needed if fancy shall select
+ * a different upsampling method. In our current implementation
+ * fancy only affects the DCT scaling, thus we can use fancy
+ * upsampling and merged upsample simultaneously, in particular
+ * with scaled DCT sizes larger than the default DCTSIZE.
+ */
+#if 0
+ if (cinfo->do_fancy_upsampling)
+ return FALSE;
+#endif
+ if (cinfo->CCIR601_sampling)
return FALSE;
/* jdmerge.c only supports YCC=>RGB color conversion */
- if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
+ if ((cinfo->jpeg_color_space != JCS_YCbCr &&
+ cinfo->jpeg_color_space != JCS_BG_YCC) ||
+ cinfo->num_components != 3 ||
cinfo->out_color_space != JCS_RGB ||
- cinfo->out_color_components != RGB_PIXELSIZE)
+ cinfo->out_color_components != RGB_PIXELSIZE ||
+ cinfo->color_transform)
return FALSE;
/* and it only handles 2h1v or 2h2v sampling ratios */
if (cinfo->comp_info[0].h_samp_factor != 2 ||
cinfo->out_color_components = 1;
break;
case JCS_RGB:
+ case JCS_BG_RGB:
cinfo->out_color_components = RGB_PIXELSIZE;
break;
case JCS_YCbCr:
+ case JCS_BG_YCC:
cinfo->out_color_components = 3;
break;
case JCS_CMYK:
* These processes all use a common table prepared by the routine below.
*
* For most steps we can mathematically guarantee that the initial value
- * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
- * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial
- * limiting step (just after the IDCT), a wildly out-of-range value is
- * possible if the input data is corrupt. To avoid any chance of indexing
+ * of x is within 2*(MAXJSAMPLE+1) of the legal range, so a table running
+ * from -2*(MAXJSAMPLE+1) to 3*MAXJSAMPLE+2 is sufficient. But for the
+ * initial limiting step (just after the IDCT), a wildly out-of-range value
+ * is possible if the input data is corrupt. To avoid any chance of indexing
* off the end of memory and getting a bad-pointer trap, we perform the
* post-IDCT limiting thus:
- * x = range_limit[x & MASK];
+ * x = (sample_range_limit - SUBSET)[(x + CENTER) & MASK];
* where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
* samples. Under normal circumstances this is more than enough range and
* a correct output will be generated; with bogus input data the mask will
* cause wraparound, and we will safely generate a bogus-but-in-range output.
* For the post-IDCT step, we want to convert the data from signed to unsigned
* representation by adding CENTERJSAMPLE at the same time that we limit it.
- * So the post-IDCT limiting table ends up looking like this:
- * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
- * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
- * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
- * 0,1,...,CENTERJSAMPLE-1
- * Negative inputs select values from the upper half of the table after
- * masking.
- *
- * We can save some space by overlapping the start of the post-IDCT table
- * with the simpler range limiting table. The post-IDCT table begins at
- * sample_range_limit + CENTERJSAMPLE.
+ * This is accomplished with SUBSET = CENTER - CENTERJSAMPLE.
*
* Note that the table is allocated in near data space on PCs; it's small
* enough and used often enough to justify this.
table = (JSAMPLE *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
- table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */
+ 5 * (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
+ /* First segment of range limit table: limit[x] = 0 for x < 0 */
+ MEMZERO(table, 2 * (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
+ table += 2 * (MAXJSAMPLE+1); /* allow negative subscripts of table */
cinfo->sample_range_limit = table;
- /* First segment of "simple" table: limit[x] = 0 for x < 0 */
- MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
- /* Main part of "simple" table: limit[x] = x */
+ /* Main part of range limit table: limit[x] = x */
for (i = 0; i <= MAXJSAMPLE; i++)
table[i] = (JSAMPLE) i;
- table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */
- /* End of simple table, rest of first half of post-IDCT table */
- for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
+ /* End of range limit table: limit[x] = MAXJSAMPLE for x > MAXJSAMPLE */
+ for (; i < 3 * (MAXJSAMPLE+1); i++)
table[i] = MAXJSAMPLE;
- /* Second half of post-IDCT table */
- MEMZERO(table + (2 * (MAXJSAMPLE+1)),
- (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
- MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
- cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
}
long samplesperrow;
JDIMENSION jd_samplesperrow;
+ /* For now, precision must match compiled-in value... */
+ if (cinfo->data_precision != BITS_IN_JSAMPLE)
+ ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
+
/* Initialize dimensions and other stuff */
jpeg_calc_output_dimensions(cinfo);
prepare_range_limit_table(cinfo);
+ /* Sanity check on image dimensions */
+ if (cinfo->output_height <= 0 || cinfo->output_width <= 0 ||
+ cinfo->out_color_components <= 0)
+ ERREXIT(cinfo, JERR_EMPTY_IMAGE);
+
/* Width of an output scanline must be representable as JDIMENSION. */
samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
jd_samplesperrow = (JDIMENSION) samplesperrow;
master = (my_master_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF(my_decomp_master));
- cinfo->master = (struct jpeg_decomp_master *) master;
+ cinfo->master = &master->pub;
master->pub.prepare_for_output_pass = prepare_for_output_pass;
master->pub.finish_output_pass = finish_output_pass;
projects / reactos.git / blobdiff