kc3-lang/libjpeg-turbo/jccolext.c
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Hash : 1e32fe31
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Date : 2015-10-14T17:32:39
Replace INT32 with a new internal datatype (JLONG) 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.
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jccolext.c
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/* * jccolext.c * * This file was part of the Independent JPEG Group's software: * Copyright (C) 1991-1996, Thomas G. Lane. * libjpeg-turbo Modifications: * Copyright (C) 2009-2012, 2015, D. R. Commander. * For conditions of distribution and use, see the accompanying README.ijg * file. * * This file contains input colorspace conversion routines. */ /* This file is included by jccolor.c */ /* * Convert some rows of samples to the JPEG colorspace. * * Note that we change from the application's interleaved-pixel format * to our internal noninterleaved, one-plane-per-component format. * The input buffer is therefore three times as wide as the output buffer. * * A starting row offset is provided only for the output buffer. The caller * can easily adjust the passed input_buf value to accommodate any row * offset required on that side. */ INLINE LOCAL(void) rgb_ycc_convert_internal (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows) { my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; register int r, g, b; register JLONG * ctab = cconvert->rgb_ycc_tab; register JSAMPROW inptr; register JSAMPROW outptr0, outptr1, outptr2; register JDIMENSION col; JDIMENSION num_cols = cinfo->image_width; while (--num_rows >= 0) { inptr = *input_buf++; outptr0 = output_buf[0][output_row]; outptr1 = output_buf[1][output_row]; outptr2 = output_buf[2][output_row]; output_row++; for (col = 0; col < num_cols; col++) { r = GETJSAMPLE(inptr[RGB_RED]); g = GETJSAMPLE(inptr[RGB_GREEN]); b = GETJSAMPLE(inptr[RGB_BLUE]); inptr += RGB_PIXELSIZE; /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations * must be too; we do not need an explicit range-limiting operation. * Hence the value being shifted is never negative, and we don't * need the general RIGHT_SHIFT macro. */ /* Y */ outptr0[col] = (JSAMPLE) ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) >> SCALEBITS); /* Cb */ outptr1[col] = (JSAMPLE) ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF]) >> SCALEBITS); /* Cr */ outptr2[col] = (JSAMPLE) ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF]) >> SCALEBITS); } } } /**************** Cases other than RGB -> YCbCr **************/ /* * Convert some rows of samples to the JPEG colorspace. * This version handles RGB->grayscale conversion, which is the same * as the RGB->Y portion of RGB->YCbCr. * We assume rgb_ycc_start has been called (we only use the Y tables). */ INLINE LOCAL(void) rgb_gray_convert_internal (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows) { my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; register int r, g, b; register JLONG * ctab = cconvert->rgb_ycc_tab; register JSAMPROW inptr; register JSAMPROW outptr; register JDIMENSION col; JDIMENSION num_cols = cinfo->image_width; while (--num_rows >= 0) { inptr = *input_buf++; outptr = output_buf[0][output_row]; output_row++; for (col = 0; col < num_cols; col++) { r = GETJSAMPLE(inptr[RGB_RED]); g = GETJSAMPLE(inptr[RGB_GREEN]); b = GETJSAMPLE(inptr[RGB_BLUE]); inptr += RGB_PIXELSIZE; /* Y */ outptr[col] = (JSAMPLE) ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) >> SCALEBITS); } } } /* * Convert some rows of samples to the JPEG colorspace. * This version handles extended RGB->plain RGB conversion */ INLINE LOCAL(void) rgb_rgb_convert_internal (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows) { register JSAMPROW inptr; register JSAMPROW outptr0, outptr1, outptr2; register JDIMENSION col; JDIMENSION num_cols = cinfo->image_width; while (--num_rows >= 0) { inptr = *input_buf++; outptr0 = output_buf[0][output_row]; outptr1 = output_buf[1][output_row]; outptr2 = output_buf[2][output_row]; output_row++; for (col = 0; col < num_cols; col++) { outptr0[col] = GETJSAMPLE(inptr[RGB_RED]); outptr1[col] = GETJSAMPLE(inptr[RGB_GREEN]); outptr2[col] = GETJSAMPLE(inptr[RGB_BLUE]); inptr += RGB_PIXELSIZE; } } }