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Eliminate support for compilers w/o unsigned char

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libjpeg-turbo has never really supported such compilers, since (AFAIK)
they are non-existent on any modern computing platform and thus
impossible for us to test.  (Also, the TurboJPEG API would break without
unsigned chars.)

Furthermore, the unified CMake-based build system introduced in 2.0
always defines HAVE_UNSIGNED_CHAR, so retaining other code paths is
pointless.  Eliminating support for compilers without unsigned char
eliminates the need for the GETJSAMPLE() macro, which improves the
readability of many parts of the code as well as improving the
performance of writing Targa and Windows BMP files.

Fixes #317
This commit is contained in:
DRC
2019-01-23 14:58:24 -06:00
parent 42d62bf114
commit 01e3032354
30 changed files with 266 additions and 388 deletions
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46
jquant2.c
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@@ -215,9 +215,9 @@ prescan_quantize(j_decompress_ptr cinfo, JSAMPARRAY input_buf,
ptr = input_buf[row];
for (col = width; col > 0; col--) {
/* get pixel value and index into the histogram */
histp = &histogram[GETJSAMPLE(ptr[0]) >> C0_SHIFT]
[GETJSAMPLE(ptr[1]) >> C1_SHIFT]
[GETJSAMPLE(ptr[2]) >> C2_SHIFT];
histp = &histogram[ptr[0] >> C0_SHIFT]
[ptr[1] >> C1_SHIFT]
[ptr[2] >> C2_SHIFT];
/* increment, check for overflow and undo increment if so. */
if (++(*histp) <= 0)
(*histp)--;
@@ -665,7 +665,7 @@ find_nearby_colors(j_decompress_ptr cinfo, int minc0, int minc1, int minc2,
for (i = 0; i < numcolors; i++) {
/* We compute the squared-c0-distance term, then add in the other two. */
x = GETJSAMPLE(cinfo->colormap[0][i]);
x = cinfo->colormap[0][i];
if (x < minc0) {
tdist = (x - minc0) * C0_SCALE;
min_dist = tdist * tdist;
@@ -688,7 +688,7 @@ find_nearby_colors(j_decompress_ptr cinfo, int minc0, int minc1, int minc2,
}
}
x = GETJSAMPLE(cinfo->colormap[1][i]);
x = cinfo->colormap[1][i];
if (x < minc1) {
tdist = (x - minc1) * C1_SCALE;
min_dist += tdist * tdist;
@@ -710,7 +710,7 @@ find_nearby_colors(j_decompress_ptr cinfo, int minc0, int minc1, int minc2,
}
}
x = GETJSAMPLE(cinfo->colormap[2][i]);
x = cinfo->colormap[2][i];
if (x < minc2) {
tdist = (x - minc2) * C2_SCALE;
min_dist += tdist * tdist;
@@ -788,13 +788,13 @@ find_best_colors(j_decompress_ptr cinfo, int minc0, int minc1, int minc2,
#define STEP_C2 ((1 << C2_SHIFT) * C2_SCALE)
for (i = 0; i < numcolors; i++) {
icolor = GETJSAMPLE(colorlist[i]);
icolor = colorlist[i];
/* Compute (square of) distance from minc0/c1/c2 to this color */
inc0 = (minc0 - GETJSAMPLE(cinfo->colormap[0][icolor])) * C0_SCALE;
inc0 = (minc0 - cinfo->colormap[0][icolor]) * C0_SCALE;
dist0 = inc0 * inc0;
inc1 = (minc1 - GETJSAMPLE(cinfo->colormap[1][icolor])) * C1_SCALE;
inc1 = (minc1 - cinfo->colormap[1][icolor]) * C1_SCALE;
dist0 += inc1 * inc1;
inc2 = (minc2 - GETJSAMPLE(cinfo->colormap[2][icolor])) * C2_SCALE;
inc2 = (minc2 - cinfo->colormap[2][icolor]) * C2_SCALE;
dist0 += inc2 * inc2;
/* Form the initial difference increments */
inc0 = inc0 * (2 * STEP_C0) + STEP_C0 * STEP_C0;
@@ -879,7 +879,7 @@ fill_inverse_cmap(j_decompress_ptr cinfo, int c0, int c1, int c2)
for (ic1 = 0; ic1 < BOX_C1_ELEMS; ic1++) {
cachep = &histogram[c0 + ic0][c1 + ic1][c2];
for (ic2 = 0; ic2 < BOX_C2_ELEMS; ic2++) {
*cachep++ = (histcell)(GETJSAMPLE(*cptr++) + 1);
*cachep++ = (histcell)((*cptr++) + 1);
}
}
}
@@ -909,9 +909,9 @@ pass2_no_dither(j_decompress_ptr cinfo, JSAMPARRAY input_buf,
outptr = output_buf[row];
for (col = width; col > 0; col--) {
/* get pixel value and index into the cache */
c0 = GETJSAMPLE(*inptr++) >> C0_SHIFT;
c1 = GETJSAMPLE(*inptr++) >> C1_SHIFT;
c2 = GETJSAMPLE(*inptr++) >> C2_SHIFT;
c0 = (*inptr++) >> C0_SHIFT;
c1 = (*inptr++) >> C1_SHIFT;
c2 = (*inptr++) >> C2_SHIFT;
cachep = &histogram[c0][c1][c2];
/* If we have not seen this color before, find nearest colormap entry */
/* and update the cache */
@@ -996,12 +996,12 @@ pass2_fs_dither(j_decompress_ptr cinfo, JSAMPARRAY input_buf,
* The maximum error is +- MAXJSAMPLE (or less with error limiting);
* this sets the required size of the range_limit array.
*/
cur0 += GETJSAMPLE(inptr[0]);
cur1 += GETJSAMPLE(inptr[1]);
cur2 += GETJSAMPLE(inptr[2]);
cur0 = GETJSAMPLE(range_limit[cur0]);
cur1 = GETJSAMPLE(range_limit[cur1]);
cur2 = GETJSAMPLE(range_limit[cur2]);
cur0 += inptr[0];
cur1 += inptr[1];
cur2 += inptr[2];
cur0 = range_limit[cur0];
cur1 = range_limit[cur1];
cur2 = range_limit[cur2];
/* Index into the cache with adjusted pixel value */
cachep =
&histogram[cur0 >> C0_SHIFT][cur1 >> C1_SHIFT][cur2 >> C2_SHIFT];
@@ -1015,9 +1015,9 @@ pass2_fs_dither(j_decompress_ptr cinfo, JSAMPARRAY input_buf,
register int pixcode = *cachep - 1;
*outptr = (JSAMPLE)pixcode;
/* Compute representation error for this pixel */
cur0 -= GETJSAMPLE(colormap0[pixcode]);
cur1 -= GETJSAMPLE(colormap1[pixcode]);
cur2 -= GETJSAMPLE(colormap2[pixcode]);
cur0 -= colormap0[pixcode];
cur1 -= colormap1[pixcode];
cur2 -= colormap2[pixcode];
}
/* Compute error fractions to be propagated to adjacent pixels.
* Add these into the running sums, and simultaneously shift the