1e32fe3113
These days, INT32 is a commonly-defined datatype in system headers. We cannot eliminate the definition of that datatype from jmorecfg.h, since the INT32 typedef has technically been part of the libjpeg API since version 5 (1994.) However, using INT32 internally is risky, because the inclusion of a particular header (Xmd.h, for instance) could change the definition of INT32 from long to int on 64-bit platforms and thus change the internal behavior of libjpeg-turbo in unexpected ways (for instance, failing to correctly set __INT32_IS_ACTUALLY_LONG to match the INT32 typedef-- perhaps as a result of including the wrong version of jpeglib.h-- could cause libjpeg-turbo to produce incorrect results.) The library has always been built in environments in which INT32 is effectively long (on Windows, long is always 32-bit, so effectively it's the same as int), so it makes sense to turn INT32 into an explicitly long datatype. This ensures that libjpeg-turbo will always behave consistently, regardless of the headers included at compile time. Addresses a concern expressed in #26.
144 lines
4.4 KiB
C
144 lines
4.4 KiB
C
/*
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* jdcolext.c
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*
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* This file was part of the Independent JPEG Group's software:
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* Copyright (C) 1991-1997, Thomas G. Lane.
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* libjpeg-turbo Modifications:
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* Copyright (C) 2009, 2011, 2015, D. R. Commander.
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* For conditions of distribution and use, see the accompanying README.ijg
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* file.
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*
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* This file contains output colorspace conversion routines.
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*/
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/* This file is included by jdcolor.c */
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/*
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* Convert some rows of samples to the output colorspace.
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*
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* Note that we change from noninterleaved, one-plane-per-component format
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* to interleaved-pixel format. The output buffer is therefore three times
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* as wide as the input buffer.
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* A starting row offset is provided only for the input buffer. The caller
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* can easily adjust the passed output_buf value to accommodate any row
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* offset required on that side.
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*/
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INLINE
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LOCAL(void)
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ycc_rgb_convert_internal (j_decompress_ptr cinfo,
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JSAMPIMAGE input_buf, JDIMENSION input_row,
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JSAMPARRAY output_buf, int num_rows)
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{
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my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
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register int y, cb, cr;
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register JSAMPROW outptr;
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register JSAMPROW inptr0, inptr1, inptr2;
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register JDIMENSION col;
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JDIMENSION num_cols = cinfo->output_width;
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/* copy these pointers into registers if possible */
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register JSAMPLE * range_limit = cinfo->sample_range_limit;
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register int * Crrtab = cconvert->Cr_r_tab;
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register int * Cbbtab = cconvert->Cb_b_tab;
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register JLONG * Crgtab = cconvert->Cr_g_tab;
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register JLONG * Cbgtab = cconvert->Cb_g_tab;
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SHIFT_TEMPS
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while (--num_rows >= 0) {
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inptr0 = input_buf[0][input_row];
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inptr1 = input_buf[1][input_row];
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inptr2 = input_buf[2][input_row];
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input_row++;
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outptr = *output_buf++;
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for (col = 0; col < num_cols; col++) {
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y = GETJSAMPLE(inptr0[col]);
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cb = GETJSAMPLE(inptr1[col]);
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cr = GETJSAMPLE(inptr2[col]);
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/* Range-limiting is essential due to noise introduced by DCT losses. */
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outptr[RGB_RED] = range_limit[y + Crrtab[cr]];
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outptr[RGB_GREEN] = range_limit[y +
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((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
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SCALEBITS))];
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outptr[RGB_BLUE] = range_limit[y + Cbbtab[cb]];
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/* Set unused byte to 0xFF so it can be interpreted as an opaque */
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/* alpha channel value */
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#ifdef RGB_ALPHA
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outptr[RGB_ALPHA] = 0xFF;
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#endif
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outptr += RGB_PIXELSIZE;
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}
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}
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}
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/*
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* Convert grayscale to RGB: just duplicate the graylevel three times.
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* This is provided to support applications that don't want to cope
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* with grayscale as a separate case.
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*/
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INLINE
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LOCAL(void)
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gray_rgb_convert_internal (j_decompress_ptr cinfo,
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JSAMPIMAGE input_buf, JDIMENSION input_row,
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JSAMPARRAY output_buf, int num_rows)
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{
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register JSAMPROW inptr, outptr;
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register JDIMENSION col;
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JDIMENSION num_cols = cinfo->output_width;
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while (--num_rows >= 0) {
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inptr = input_buf[0][input_row++];
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outptr = *output_buf++;
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for (col = 0; col < num_cols; col++) {
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/* We can dispense with GETJSAMPLE() here */
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outptr[RGB_RED] = outptr[RGB_GREEN] = outptr[RGB_BLUE] = inptr[col];
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/* Set unused byte to 0xFF so it can be interpreted as an opaque */
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/* alpha channel value */
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#ifdef RGB_ALPHA
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outptr[RGB_ALPHA] = 0xFF;
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#endif
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outptr += RGB_PIXELSIZE;
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}
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}
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}
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/*
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* Convert RGB to extended RGB: just swap the order of source pixels
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*/
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INLINE
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LOCAL(void)
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rgb_rgb_convert_internal (j_decompress_ptr cinfo,
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JSAMPIMAGE input_buf, JDIMENSION input_row,
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JSAMPARRAY output_buf, int num_rows)
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{
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register JSAMPROW inptr0, inptr1, inptr2;
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register JSAMPROW outptr;
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register JDIMENSION col;
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JDIMENSION num_cols = cinfo->output_width;
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while (--num_rows >= 0) {
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inptr0 = input_buf[0][input_row];
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inptr1 = input_buf[1][input_row];
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inptr2 = input_buf[2][input_row];
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input_row++;
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outptr = *output_buf++;
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for (col = 0; col < num_cols; col++) {
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/* We can dispense with GETJSAMPLE() here */
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outptr[RGB_RED] = inptr0[col];
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outptr[RGB_GREEN] = inptr1[col];
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outptr[RGB_BLUE] = inptr2[col];
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/* Set unused byte to 0xFF so it can be interpreted as an opaque */
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/* alpha channel value */
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#ifdef RGB_ALPHA
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outptr[RGB_ALPHA] = 0xFF;
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#endif
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outptr += RGB_PIXELSIZE;
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}
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}
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}
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