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-rw-r--r--jpeg/jdcolor.c93
1 files changed, 42 insertions, 51 deletions
diff --git a/jpeg/jdcolor.c b/jpeg/jdcolor.c
index 7750df125..6b40fb534 100644
--- a/jpeg/jdcolor.c
+++ b/jpeg/jdcolor.c
@@ -2,7 +2,7 @@
* jdcolor.c
*
* Copyright (C) 1991-1997, Thomas G. Lane.
- * Modified 2011-2020 by Guido Vollbeding.
+ * Modified 2011-2023 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.
*
@@ -32,7 +32,9 @@ typedef struct {
INT32 * Cb_g_tab; /* => table for Cb to G conversion */
/* Private state for RGB->Y conversion */
- INT32 * rgb_y_tab; /* => table for RGB to Y conversion */
+ INT32 * R_y_tab; /* => table for R to Y conversion */
+ INT32 * G_y_tab; /* => table for G to Y conversion */
+ INT32 * B_y_tab; /* => table for B to Y conversion */
} my_color_deconverter;
typedef my_color_deconverter * my_cconvert_ptr;
@@ -87,29 +89,17 @@ typedef my_color_deconverter * my_cconvert_ptr;
* by precalculating the constants times Cb and Cr for all possible values.
* For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
* for 9-bit to 12-bit samples it is still acceptable. It's not very
- * reasonable for 16-bit samples, but if you want lossless storage you
- * shouldn't be changing colorspace anyway.
- * The Cr=>R and Cb=>B values can be rounded to integers in advance; the
- * values for the G calculation are left scaled up, since we must add them
- * together before rounding.
+ * reasonable for 16-bit samples, but if you want lossless storage
+ * you shouldn't be changing colorspace anyway.
+ * The Cr=>R and Cb=>B values can be rounded to integers in advance;
+ * the values for the G calculation are left scaled up,
+ * since we must add them together before rounding.
*/
#define SCALEBITS 16 /* speediest right-shift on some machines */
#define ONE_HALF ((INT32) 1 << (SCALEBITS-1))
#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
-/* We allocate one big table for RGB->Y conversion and divide it up into
- * three parts, instead of doing three alloc_small requests. This lets us
- * use a single table base address, which can be held in a register in the
- * inner loops on many machines (more than can hold all three addresses,
- * anyway).
- */
-
-#define R_Y_OFF 0 /* offset to R => Y section */
-#define G_Y_OFF (1*(MAXJSAMPLE+1)) /* offset to G => Y section */
-#define B_Y_OFF (2*(MAXJSAMPLE+1)) /* etc. */
-#define TABLE_SIZE (3*(MAXJSAMPLE+1))
-
/*
* Initialize tables for YCbCr->RGB and BG_YCC->RGB colorspace conversion.
@@ -249,17 +239,19 @@ LOCAL(void)
build_rgb_y_table (j_decompress_ptr cinfo)
{
my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
- INT32 * rgb_y_tab;
INT32 i;
- /* Allocate and fill in the conversion tables. */
- cconvert->rgb_y_tab = rgb_y_tab = (INT32 *) (*cinfo->mem->alloc_small)
- ((j_common_ptr) cinfo, JPOOL_IMAGE, TABLE_SIZE * SIZEOF(INT32));
+ cconvert->R_y_tab = (INT32 *) (*cinfo->mem->alloc_small)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, (MAXJSAMPLE+1) * SIZEOF(INT32));
+ cconvert->G_y_tab = (INT32 *) (*cinfo->mem->alloc_small)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, (MAXJSAMPLE+1) * SIZEOF(INT32));
+ cconvert->B_y_tab = (INT32 *) (*cinfo->mem->alloc_small)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, (MAXJSAMPLE+1) * SIZEOF(INT32));
for (i = 0; i <= MAXJSAMPLE; i++) {
- rgb_y_tab[i+R_Y_OFF] = FIX(0.299) * i;
- rgb_y_tab[i+G_Y_OFF] = FIX(0.587) * i;
- rgb_y_tab[i+B_Y_OFF] = FIX(0.114) * i + ONE_HALF;
+ cconvert->R_y_tab[i] = FIX(0.299) * i;
+ cconvert->G_y_tab[i] = FIX(0.587) * i;
+ cconvert->B_y_tab[i] = FIX(0.114) * i + ONE_HALF;
}
}
@@ -274,8 +266,10 @@ rgb_gray_convert (j_decompress_ptr cinfo,
JSAMPARRAY output_buf, int num_rows)
{
my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
- register int r, g, b;
- register INT32 * ctab = cconvert->rgb_y_tab;
+ register INT32 y;
+ register INT32 * Rytab = cconvert->R_y_tab;
+ register INT32 * Gytab = cconvert->G_y_tab;
+ register INT32 * Bytab = cconvert->B_y_tab;
register JSAMPROW outptr;
register JSAMPROW inptr0, inptr1, inptr2;
register JDIMENSION col;
@@ -288,13 +282,10 @@ rgb_gray_convert (j_decompress_ptr cinfo,
input_row++;
outptr = *output_buf++;
for (col = 0; col < num_cols; col++) {
- r = GETJSAMPLE(inptr0[col]);
- g = GETJSAMPLE(inptr1[col]);
- b = GETJSAMPLE(inptr2[col]);
- /* Y */
- outptr[col] = (JSAMPLE)
- ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
- >> SCALEBITS);
+ y = Rytab[GETJSAMPLE(inptr0[col])];
+ y += Gytab[GETJSAMPLE(inptr1[col])];
+ y += Bytab[GETJSAMPLE(inptr2[col])];
+ outptr[col] = (JSAMPLE) (y >> SCALEBITS);
}
}
}
@@ -354,7 +345,10 @@ rgb1_gray_convert (j_decompress_ptr cinfo,
{
my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
register int r, g, b;
- register INT32 * ctab = cconvert->rgb_y_tab;
+ register INT32 y;
+ register INT32 * Rytab = cconvert->R_y_tab;
+ register INT32 * Gytab = cconvert->G_y_tab;
+ register INT32 * Bytab = cconvert->B_y_tab;
register JSAMPROW outptr;
register JSAMPROW inptr0, inptr1, inptr2;
register JDIMENSION col;
@@ -373,12 +367,10 @@ rgb1_gray_convert (j_decompress_ptr cinfo,
/* Assume that MAXJSAMPLE+1 is a power of 2, so that the MOD
* (modulo) operator is equivalent to the bitmask operator AND.
*/
- r = (r + g - CENTERJSAMPLE) & MAXJSAMPLE;
- b = (b + g - CENTERJSAMPLE) & MAXJSAMPLE;
- /* Y */
- outptr[col] = (JSAMPLE)
- ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
- >> SCALEBITS);
+ y = Rytab[(r + g - CENTERJSAMPLE) & MAXJSAMPLE];
+ y += Gytab[g];
+ y += Bytab[(b + g - CENTERJSAMPLE) & MAXJSAMPLE];
+ outptr[col] = (JSAMPLE) (y >> SCALEBITS);
}
}
}
@@ -565,8 +557,10 @@ cmyk_yk_convert (j_decompress_ptr cinfo,
JSAMPARRAY output_buf, int num_rows)
{
my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
- register int r, g, b;
- register INT32 * ctab = cconvert->rgb_y_tab;
+ register INT32 y;
+ register INT32 * Rytab = cconvert->R_y_tab;
+ register INT32 * Gytab = cconvert->G_y_tab;
+ register INT32 * Bytab = cconvert->B_y_tab;
register JSAMPROW outptr;
register JSAMPROW inptr0, inptr1, inptr2, inptr3;
register JDIMENSION col;
@@ -580,13 +574,10 @@ cmyk_yk_convert (j_decompress_ptr cinfo,
input_row++;
outptr = *output_buf++;
for (col = 0; col < num_cols; col++) {
- r = MAXJSAMPLE - GETJSAMPLE(inptr0[col]);
- g = MAXJSAMPLE - GETJSAMPLE(inptr1[col]);
- b = MAXJSAMPLE - GETJSAMPLE(inptr2[col]);
- /* Y */
- outptr[0] = (JSAMPLE)
- ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
- >> SCALEBITS);
+ y = Rytab[MAXJSAMPLE - GETJSAMPLE(inptr0[col])];
+ y += Gytab[MAXJSAMPLE - GETJSAMPLE(inptr1[col])];
+ y += Bytab[MAXJSAMPLE - GETJSAMPLE(inptr2[col])];
+ outptr[0] = (JSAMPLE) (y >> SCALEBITS);
/* K passes through unchanged */
outptr[1] = inptr3[col]; /* don't need GETJSAMPLE here */
outptr += 2;
generated by cgit v1.2.3 (git 2.25.1) at 2026-02-08 08:34:08 +0000