/*
 * jccolor.c
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1991-1996, Thomas G. Lane.
 * libjpeg-turbo Modifications:
 * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
 * Copyright (C) 2009-2012, 2015, D. R. Commander.
 * Copyright (C) 2014, MIPS Technologies, Inc., California.
 * For conditions of distribution and use, see the accompanying README.ijg
 * file.
 *
 * This file contains input colorspace conversion routines.
 */

#define JPEG_INTERNALS

#include "jinclude.h"
#include "jpeglib.h"
#include "jsimd.h"
#include "jconfigint.h"


/* Private subobject */

typedef struct {
	struct jpeg_color_converter pub; /* public fields */

	/* Private state for RGB->YCC conversion */
	JLONG *rgb_ycc_tab;           /* => table for RGB to YCbCr conversion */
} my_color_converter;

typedef my_color_converter *my_cconvert_ptr;


/**************** RGB -> YCbCr conversion: most common case **************/

/*
 * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
 * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
 * The conversion equations to be implemented are therefore
 *      Y  =  0.29900 * R + 0.58700 * G + 0.11400 * B
 *      Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B  + CENTERJSAMPLE
 *      Cr =  0.50000 * R - 0.41869 * G - 0.08131 * B  + CENTERJSAMPLE
 * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
 * Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2,
 * rather than CENTERJSAMPLE, for Cb and Cr.  This gave equal positive and
 * negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0)
 * were not represented exactly.  Now we sacrifice exact representation of
 * maximum red and maximum blue in order to get exact grayscales.
 *
 * To avoid floating-point arithmetic, we represent the fractional constants
 * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
 * the products by 2^16, with appropriate rounding, to get the correct answer.
 *
 * For even more speed, we avoid doing any multiplications in the inner loop
 * by precalculating the constants times R,G,B for all possible values.
 * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
 * for 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 CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included
 * in the tables to save adding them separately in the inner loop.
 */

#define SCALEBITS       16      /* speediest right-shift on some machines */
#define CBCR_OFFSET     ((JLONG) CENTERJSAMPLE << SCALEBITS)
#define ONE_HALF        ((JLONG) 1 << (SCALEBITS-1))
#define FIX(x)          ((JLONG) ((x) * (1L<<SCALEBITS) + 0.5))

/* We allocate one big table and divide it up into eight parts, instead of
 * doing eight 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 eight 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 R_CB_OFF        (3*(MAXJSAMPLE+1))
#define G_CB_OFF        (4*(MAXJSAMPLE+1))
#define B_CB_OFF        (5*(MAXJSAMPLE+1))
#define R_CR_OFF        B_CB_OFF                /* B=>Cb, R=>Cr are the same */
#define G_CR_OFF        (6*(MAXJSAMPLE+1))
#define B_CR_OFF        (7*(MAXJSAMPLE+1))
#define TABLE_SIZE      (8*(MAXJSAMPLE+1))


/* Include inline routines for colorspace extensions */

#include "jccolext.c"

#undef RGB_RED
#undef RGB_GREEN
#undef RGB_BLUE
#undef RGB_PIXELSIZE

#define RGB_RED EXT_RGB_RED
#define RGB_GREEN EXT_RGB_GREEN
#define RGB_BLUE EXT_RGB_BLUE
#define RGB_PIXELSIZE EXT_RGB_PIXELSIZE
#define rgb_ycc_convert_internal extrgb_ycc_convert_internal
#define rgb_gray_convert_internal extrgb_gray_convert_internal
#define rgb_rgb_convert_internal extrgb_rgb_convert_internal

#include "jccolext.c"

#undef RGB_RED
#undef RGB_GREEN
#undef RGB_BLUE
#undef RGB_PIXELSIZE
#undef rgb_ycc_convert_internal
#undef rgb_gray_convert_internal
#undef rgb_rgb_convert_internal

#define RGB_RED EXT_RGBX_RED
#define RGB_GREEN EXT_RGBX_GREEN
#define RGB_BLUE EXT_RGBX_BLUE
#define RGB_PIXELSIZE EXT_RGBX_PIXELSIZE
#define rgb_ycc_convert_internal extrgbx_ycc_convert_internal
#define rgb_gray_convert_internal extrgbx_gray_convert_internal
#define rgb_rgb_convert_internal extrgbx_rgb_convert_internal

#include "jccolext.c"

#undef RGB_RED
#undef RGB_GREEN
#undef RGB_BLUE
#undef RGB_PIXELSIZE
#undef rgb_ycc_convert_internal
#undef rgb_gray_convert_internal
#undef rgb_rgb_convert_internal

#define RGB_RED EXT_BGR_RED
#define RGB_GREEN EXT_BGR_GREEN
#define RGB_BLUE EXT_BGR_BLUE
#define RGB_PIXELSIZE EXT_BGR_PIXELSIZE
#define rgb_ycc_convert_internal extbgr_ycc_convert_internal
#define rgb_gray_convert_internal extbgr_gray_convert_internal
#define rgb_rgb_convert_internal extbgr_rgb_convert_internal

#include "jccolext.c"

#undef RGB_RED
#undef RGB_GREEN
#undef RGB_BLUE
#undef RGB_PIXELSIZE
#undef rgb_ycc_convert_internal
#undef rgb_gray_convert_internal
#undef rgb_rgb_convert_internal

#define RGB_RED EXT_BGRX_RED
#define RGB_GREEN EXT_BGRX_GREEN
#define RGB_BLUE EXT_BGRX_BLUE
#define RGB_PIXELSIZE EXT_BGRX_PIXELSIZE
#define rgb_ycc_convert_internal extbgrx_ycc_convert_internal
#define rgb_gray_convert_internal extbgrx_gray_convert_internal
#define rgb_rgb_convert_internal extbgrx_rgb_convert_internal

#include "jccolext.c"

#undef RGB_RED
#undef RGB_GREEN
#undef RGB_BLUE
#undef RGB_PIXELSIZE
#undef rgb_ycc_convert_internal
#undef rgb_gray_convert_internal
#undef rgb_rgb_convert_internal

#define RGB_RED EXT_XBGR_RED
#define RGB_GREEN EXT_XBGR_GREEN
#define RGB_BLUE EXT_XBGR_BLUE
#define RGB_PIXELSIZE EXT_XBGR_PIXELSIZE
#define rgb_ycc_convert_internal extxbgr_ycc_convert_internal
#define rgb_gray_convert_internal extxbgr_gray_convert_internal
#define rgb_rgb_convert_internal extxbgr_rgb_convert_internal

#include "jccolext.c"

#undef RGB_RED
#undef RGB_GREEN
#undef RGB_BLUE
#undef RGB_PIXELSIZE
#undef rgb_ycc_convert_internal
#undef rgb_gray_convert_internal
#undef rgb_rgb_convert_internal

#define RGB_RED EXT_XRGB_RED
#define RGB_GREEN EXT_XRGB_GREEN
#define RGB_BLUE EXT_XRGB_BLUE
#define RGB_PIXELSIZE EXT_XRGB_PIXELSIZE
#define rgb_ycc_convert_internal extxrgb_ycc_convert_internal
#define rgb_gray_convert_internal extxrgb_gray_convert_internal
#define rgb_rgb_convert_internal extxrgb_rgb_convert_internal

#include "jccolext.c"

#undef RGB_RED
#undef RGB_GREEN
#undef RGB_BLUE
#undef RGB_PIXELSIZE
#undef rgb_ycc_convert_internal
#undef rgb_gray_convert_internal
#undef rgb_rgb_convert_internal


/*
 * Initialize for RGB->YCC colorspace conversion.
 */

METHODDEF(void)
rgb_ycc_start(j_compress_ptr cinfo) {
	my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
	JLONG *rgb_ycc_tab;
	JLONG i;

	/* Allocate and fill in the conversion tables. */
	cconvert->rgb_ycc_tab = rgb_ycc_tab = (JLONG *)
			(*cinfo->mem->alloc_small)((j_common_ptr) cinfo, JPOOL_IMAGE,
			                           (TABLE_SIZE * sizeof(JLONG)));

	for (i = 0; i <= MAXJSAMPLE; i++) {
		rgb_ycc_tab[i + R_Y_OFF] = FIX(0.29900) * i;
		rgb_ycc_tab[i + G_Y_OFF] = FIX(0.58700) * i;
		rgb_ycc_tab[i + B_Y_OFF] = FIX(0.11400) * i + ONE_HALF;
		rgb_ycc_tab[i + R_CB_OFF] = (-FIX(0.16874)) * i;
		rgb_ycc_tab[i + G_CB_OFF] = (-FIX(0.33126)) * i;
		/* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
		 * This ensures that the maximum output will round to MAXJSAMPLE
		 * not MAXJSAMPLE+1, and thus that we don't have to range-limit.
		 */
		rgb_ycc_tab[i + B_CB_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF - 1;
/*  B=>Cb and R=>Cr tables are the same
    rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
*/
		rgb_ycc_tab[i + G_CR_OFF] = (-FIX(0.41869)) * i;
		rgb_ycc_tab[i + B_CR_OFF] = (-FIX(0.08131)) * i;
	}
}


/*
 * Convert some rows of samples to the JPEG colorspace.
 */

METHODDEF(void)
rgb_ycc_convert(j_compress_ptr cinfo,
                JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
                JDIMENSION output_row, int num_rows) {
	switch (cinfo->in_color_space) {
		case JCS_EXT_RGB:
			extrgb_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
			                            num_rows);
			break;
		case JCS_EXT_RGBX:
		case JCS_EXT_RGBA:
			extrgbx_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		case JCS_EXT_BGR:
			extbgr_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
			                            num_rows);
			break;
		case JCS_EXT_BGRX:
		case JCS_EXT_BGRA:
			extbgrx_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		case JCS_EXT_XBGR:
		case JCS_EXT_ABGR:
			extxbgr_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		case JCS_EXT_XRGB:
		case JCS_EXT_ARGB:
			extxrgb_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		default:
			rgb_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
			                         num_rows);
			break;
	}
}


/**************** Cases other than RGB -> YCbCr **************/


/*
 * Convert some rows of samples to the JPEG colorspace.
 */

METHODDEF(void)
rgb_gray_convert(j_compress_ptr cinfo,
                 JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
                 JDIMENSION output_row, int num_rows) {
	switch (cinfo->in_color_space) {
		case JCS_EXT_RGB:
			extrgb_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		case JCS_EXT_RGBX:
		case JCS_EXT_RGBA:
			extrgbx_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
			                              num_rows);
			break;
		case JCS_EXT_BGR:
			extbgr_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		case JCS_EXT_BGRX:
		case JCS_EXT_BGRA:
			extbgrx_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
			                              num_rows);
			break;
		case JCS_EXT_XBGR:
		case JCS_EXT_ABGR:
			extxbgr_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
			                              num_rows);
			break;
		case JCS_EXT_XRGB:
		case JCS_EXT_ARGB:
			extxrgb_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
			                              num_rows);
			break;
		default:
			rgb_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
			                          num_rows);
			break;
	}
}


/*
 * Extended RGB to plain RGB conversion
 */

METHODDEF(void)
rgb_rgb_convert(j_compress_ptr cinfo,
                JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
                JDIMENSION output_row, int num_rows) {
	switch (cinfo->in_color_space) {
		case JCS_EXT_RGB:
			extrgb_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
			                            num_rows);
			break;
		case JCS_EXT_RGBX:
		case JCS_EXT_RGBA:
			extrgbx_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		case JCS_EXT_BGR:
			extbgr_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
			                            num_rows);
			break;
		case JCS_EXT_BGRX:
		case JCS_EXT_BGRA:
			extbgrx_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		case JCS_EXT_XBGR:
		case JCS_EXT_ABGR:
			extxbgr_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		case JCS_EXT_XRGB:
		case JCS_EXT_ARGB:
			extxrgb_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
			                             num_rows);
			break;
		default:
			rgb_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
			                         num_rows);
			break;
	}
}


/*
 * Convert some rows of samples to the JPEG colorspace.
 * This version handles Adobe-style CMYK->YCCK conversion,
 * where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same
 * conversion as above, while passing K (black) unchanged.
 * We assume rgb_ycc_start has been called.
 */

METHODDEF(void)
cmyk_ycck_convert(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, outptr3;
	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];
		outptr3 = output_buf[3][output_row];
		output_row++;
		for (col = 0; col < num_cols; col++) {
			r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
			g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
			b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
			/* K passes through as-is */
			outptr3[col] = inptr[3];  /* don't need GETJSAMPLE here */
			inptr += 4;
			/* 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);
		}
	}
}


/*
 * Convert some rows of samples to the JPEG colorspace.
 * This version handles grayscale output with no conversion.
 * The source can be either plain grayscale or YCbCr (since Y == gray).
 */

METHODDEF(void)
grayscale_convert(j_compress_ptr cinfo,
                  JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
                  JDIMENSION output_row, int num_rows) {
	register JSAMPROW inptr;
	register JSAMPROW outptr;
	register JDIMENSION col;
	JDIMENSION num_cols = cinfo->image_width;
	int instride = cinfo->input_components;

	while (--num_rows >= 0) {
		inptr = *input_buf++;
		outptr = output_buf[0][output_row];
		output_row++;
		for (col = 0; col < num_cols; col++) {
			outptr[col] = inptr[0];   /* don't need GETJSAMPLE() here */
			inptr += instride;
		}
	}
}


/*
 * Convert some rows of samples to the JPEG colorspace.
 * This version handles multi-component colorspaces without conversion.
 * We assume input_components == num_components.
 */

METHODDEF(void)
null_convert(j_compress_ptr cinfo,
             JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
             JDIMENSION output_row, int num_rows) {
	register JSAMPROW inptr;
	register JSAMPROW outptr, outptr0, outptr1, outptr2, outptr3;
	register JDIMENSION col;
	register int ci;
	int nc = cinfo->num_components;
	JDIMENSION num_cols = cinfo->image_width;

	if (nc == 3) {
		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] = *inptr++;
				outptr1[col] = *inptr++;
				outptr2[col] = *inptr++;
			}
		}
	} else if (nc == 4) {
		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];
			outptr3 = output_buf[3][output_row];
			output_row++;
			for (col = 0; col < num_cols; col++) {
				outptr0[col] = *inptr++;
				outptr1[col] = *inptr++;
				outptr2[col] = *inptr++;
				outptr3[col] = *inptr++;
			}
		}
	} else {
		while (--num_rows >= 0) {
			/* It seems fastest to make a separate pass for each component. */
			for (ci = 0; ci < nc; ci++) {
				inptr = *input_buf;
				outptr = output_buf[ci][output_row];
				for (col = 0; col < num_cols; col++) {
					outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */
					inptr += nc;
				}
			}
			input_buf++;
			output_row++;
		}
	}
}


/*
 * Empty method for start_pass.
 */

METHODDEF(void)
null_method(j_compress_ptr cinfo) {
	/* no work needed */
}


/*
 * Module initialization routine for input colorspace conversion.
 */

GLOBAL(void)
jinit_color_converter(j_compress_ptr cinfo) {
	my_cconvert_ptr cconvert;

	cconvert = (my_cconvert_ptr)
			(*cinfo->mem->alloc_small)((j_common_ptr) cinfo, JPOOL_IMAGE,
			                           sizeof(my_color_converter));
	cinfo->cconvert = (struct jpeg_color_converter *) cconvert;
	/* set start_pass to null method until we find out differently */
	cconvert->pub.start_pass = null_method;

	/* Make sure input_components agrees with in_color_space */
	switch (cinfo->in_color_space) {
		case JCS_GRAYSCALE:
			if (cinfo->input_components != 1)
				ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
			break;

		case JCS_RGB:
		case JCS_EXT_RGB:
		case JCS_EXT_RGBX:
		case JCS_EXT_BGR:
		case JCS_EXT_BGRX:
		case JCS_EXT_XBGR:
		case JCS_EXT_XRGB:
		case JCS_EXT_RGBA:
		case JCS_EXT_BGRA:
		case JCS_EXT_ABGR:
		case JCS_EXT_ARGB:
			if (cinfo->input_components != rgb_pixelsize[cinfo->in_color_space])
				ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
			break;

		case JCS_YCbCr:
			if (cinfo->input_components != 3)
				ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
			break;

		case JCS_CMYK:
		case JCS_YCCK:
			if (cinfo->input_components != 4)
				ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
			break;

		default:                      /* JCS_UNKNOWN can be anything */
			if (cinfo->input_components < 1)
				ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
			break;
	}

	/* Check num_components, set conversion method based on requested space */
	switch (cinfo->jpeg_color_space) {
		case JCS_GRAYSCALE:
			if (cinfo->num_components != 1)
				ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
			if (cinfo->in_color_space == JCS_GRAYSCALE)
				cconvert->pub.color_convert = grayscale_convert;
			else if (cinfo->in_color_space == JCS_RGB ||
			         cinfo->in_color_space == JCS_EXT_RGB ||
			         cinfo->in_color_space == JCS_EXT_RGBX ||
			         cinfo->in_color_space == JCS_EXT_BGR ||
			         cinfo->in_color_space == JCS_EXT_BGRX ||
			         cinfo->in_color_space == JCS_EXT_XBGR ||
			         cinfo->in_color_space == JCS_EXT_XRGB ||
			         cinfo->in_color_space == JCS_EXT_RGBA ||
			         cinfo->in_color_space == JCS_EXT_BGRA ||
			         cinfo->in_color_space == JCS_EXT_ABGR ||
			         cinfo->in_color_space == JCS_EXT_ARGB) {
				if (jsimd_can_rgb_gray())
					cconvert->pub.color_convert = jsimd_rgb_gray_convert;
				else {
					cconvert->pub.start_pass = rgb_ycc_start;
					cconvert->pub.color_convert = rgb_gray_convert;
				}
			} else if (cinfo->in_color_space == JCS_YCbCr)
				cconvert->pub.color_convert = grayscale_convert;
			else
				ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
			break;

		case JCS_RGB:
			if (cinfo->num_components != 3)
				ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
			if (rgb_red[cinfo->in_color_space] == 0 &&
			    rgb_green[cinfo->in_color_space] == 1 &&
			    rgb_blue[cinfo->in_color_space] == 2 &&
			    rgb_pixelsize[cinfo->in_color_space] == 3) {
#if defined(__mips__)
				if (jsimd_c_can_null_convert())
				  cconvert->pub.color_convert = jsimd_c_null_convert;
				else
#endif
				cconvert->pub.color_convert = null_convert;
			} else if (cinfo->in_color_space == JCS_RGB ||
			           cinfo->in_color_space == JCS_EXT_RGB ||
			           cinfo->in_color_space == JCS_EXT_RGBX ||
			           cinfo->in_color_space == JCS_EXT_BGR ||
			           cinfo->in_color_space == JCS_EXT_BGRX ||
			           cinfo->in_color_space == JCS_EXT_XBGR ||
			           cinfo->in_color_space == JCS_EXT_XRGB ||
			           cinfo->in_color_space == JCS_EXT_RGBA ||
			           cinfo->in_color_space == JCS_EXT_BGRA ||
			           cinfo->in_color_space == JCS_EXT_ABGR ||
			           cinfo->in_color_space == JCS_EXT_ARGB)
				cconvert->pub.color_convert = rgb_rgb_convert;
			else
				ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
			break;

		case JCS_YCbCr:
			if (cinfo->num_components != 3)
				ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
			if (cinfo->in_color_space == JCS_RGB ||
			    cinfo->in_color_space == JCS_EXT_RGB ||
			    cinfo->in_color_space == JCS_EXT_RGBX ||
			    cinfo->in_color_space == JCS_EXT_BGR ||
			    cinfo->in_color_space == JCS_EXT_BGRX ||
			    cinfo->in_color_space == JCS_EXT_XBGR ||
			    cinfo->in_color_space == JCS_EXT_XRGB ||
			    cinfo->in_color_space == JCS_EXT_RGBA ||
			    cinfo->in_color_space == JCS_EXT_BGRA ||
			    cinfo->in_color_space == JCS_EXT_ABGR ||
			    cinfo->in_color_space == JCS_EXT_ARGB) {
				if (jsimd_can_rgb_ycc())
					cconvert->pub.color_convert = jsimd_rgb_ycc_convert;
				else {
					cconvert->pub.start_pass = rgb_ycc_start;
					cconvert->pub.color_convert = rgb_ycc_convert;
				}
			} else if (cinfo->in_color_space == JCS_YCbCr) {
#if defined(__mips__)
				if (jsimd_c_can_null_convert())
				  cconvert->pub.color_convert = jsimd_c_null_convert;
				else
#endif
				cconvert->pub.color_convert = null_convert;
			} else
				ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
			break;

		case JCS_CMYK:
			if (cinfo->num_components != 4)
				ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
			if (cinfo->in_color_space == JCS_CMYK) {
#if defined(__mips__)
				if (jsimd_c_can_null_convert())
				  cconvert->pub.color_convert = jsimd_c_null_convert;
				else
#endif
				cconvert->pub.color_convert = null_convert;
			} else
				ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
			break;

		case JCS_YCCK:
			if (cinfo->num_components != 4)
				ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
			if (cinfo->in_color_space == JCS_CMYK) {
				cconvert->pub.start_pass = rgb_ycc_start;
				cconvert->pub.color_convert = cmyk_ycck_convert;
			} else if (cinfo->in_color_space == JCS_YCCK) {
#if defined(__mips__)
				if (jsimd_c_can_null_convert())
				  cconvert->pub.color_convert = jsimd_c_null_convert;
				else
#endif
				cconvert->pub.color_convert = null_convert;
			} else
				ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
			break;

		default:                      /* allow null conversion of JCS_UNKNOWN */
			if (cinfo->jpeg_color_space != cinfo->in_color_space ||
			    cinfo->num_components != cinfo->input_components)
				ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
#if defined(__mips__)
		if (jsimd_c_can_null_convert())
		  cconvert->pub.color_convert = jsimd_c_null_convert;
		else
#endif
			cconvert->pub.color_convert = null_convert;
			break;
	}
}
