/* See LICENSE file for copyright and license details. */

#if defined(__GNUC__) && !defined(__clang__)
# pragma GCC diagnostic ignored "-Wfloat-equal"
#elif defined(__clang__)
# pragma clang diagnostic ignored "-Wcomma"
# pragma clang diagnostic ignored "-Wfloat-equal"
# pragma clang diagnostic ignored "-Wvla"
# pragma clang diagnostic ignored "-Wtautological-compare"
# pragma clang diagnostic ignored "-Wcovered-switch-default"
# pragma clang diagnostic ignored "-Wfloat-conversion"
# pragma clang diagnostic ignored "-Wconversion"
# pragma clang diagnostic ignored "-Wdouble-promotion"
# pragma clang diagnostic ignored "-Wswitch-enum"
# pragma clang diagnostic ignored "-Wcast-align"
#endif


#define PI          D(3.14159265358979323846)
#define PI2         (2 * D(3.14159265358979323846))
#define WASDIV0(X)  (xisinf(X) || xisnan(X))

#define REGULAR(S, T)    ((T) <= (S)->TRANSITION ? (S)->SLOPE * (T) : (1 + (S)->OFFSET) * xpow((T), 1 / (S)->GAMMA) - (S)->OFFSET)
#define INVREGULAR(S, T) ((T) <= (S)->TRANSITIONINV ? (T) / (S)->SLOPE : xpow(((T) + (S)->OFFSET) / (1 + (S)->OFFSET), (S)->GAMMA))

#define TRANSFORM(X, Y, Z, A, B, C, R1C1, R1C2, R1C3, R2C1, R2C2, R2C3, R3C1, R3C2, R3C3)\
	do {\
		TYPE a__ = (A), b__ = (B), c__ = (C);\
		(X) = D(R1C1) * a__ + D(R1C2) * b__ + D(R1C3) * c__;\
		(Y) = D(R2C1) * a__ + D(R2C2) * b__ + D(R2C3) * c__;\
		(Z) = D(R3C1) * a__ + D(R3C2) * b__ + D(R3C3) * c__;\
	} while (0)



#define SLOPE transfer.regular.slope
#define TRANSITIONINV transfer.regular.transitioninv
#define TRANSITION transfer.regular.transition
#define GAMMA transfer.regular.gamma
#define OFFSET transfer.regular.offset
#define TO_ENCODED_RED transfer.custom.to_encoded_red
#define TO_DECODED_RED transfer.custom.to_decoded_red
#define TO_ENCODED_GREEN transfer.custom.to_encoded_green
#define TO_DECODED_GREEN transfer.custom.to_decoded_green
#define TO_ENCODED_BLUE transfer.custom.to_encoded_blue
#define TO_DECODED_BLUE transfer.custom.to_decoded_blue



static void to_rgb(const libcolour_colour_t *restrict from, libcolour_rgb_t *restrict to);
static void to_srgb(const libcolour_colour_t *restrict from, libcolour_srgb_t *restrict to);
static void to_ciexyy(const libcolour_colour_t *restrict from, libcolour_ciexyy_t *restrict to);
static void to_ciexyz(const libcolour_colour_t *restrict from, libcolour_ciexyz_t *restrict to);
static void to_cielab(const libcolour_colour_t *restrict from, libcolour_cielab_t *restrict to);
static void to_cieluv(const libcolour_colour_t *restrict from, libcolour_cieluv_t *restrict to);
static void to_cielchuv(const libcolour_colour_t *restrict from, libcolour_cielchuv_t *restrict to);
static void to_yiq(const libcolour_colour_t *restrict from, libcolour_yiq_t *restrict to);
static void to_ydbdr(const libcolour_colour_t *restrict from, libcolour_ydbdr_t *restrict to);
static void to_yuv(const libcolour_colour_t *restrict from, libcolour_yuv_t *restrict to);
static void to_ypbpr(const libcolour_colour_t *restrict from, libcolour_ypbpr_t *restrict to);
static void to_ycgco(const libcolour_colour_t *restrict from, libcolour_ycgco_t *restrict to);
static void to_cie1960ucs(const libcolour_colour_t *restrict from, libcolour_cie1960ucs_t *restrict to);
static void to_cieuvw(const libcolour_colour_t *restrict from, libcolour_cieuvw_t *restrict to);



static void
ciexyz_to_rgb(const libcolour_ciexyz_t *restrict from, libcolour_rgb_t *restrict to)
{
	TYPE X = from->X, Y = from->Y, Z = from->Z;
	to->R = to->Minv[0][0] * X + to->Minv[0][1] * Y + to->Minv[0][2] * Z;
	to->G = to->Minv[1][0] * X + to->Minv[1][1] * Y + to->Minv[1][2] * Z;
	to->B = to->Minv[2][0] * X + to->Minv[2][1] * Y + to->Minv[2][2] * Z;
}


static void
rgb_encode(libcolour_rgb_t *restrict colour, const libcolour_rgb_t *restrict space)
{
	TYPE r_sign = 1, g_sign = 1, b_sign = 1;
	switch (space->encoding_type) {
	case LIBCOLOUR_ENCODING_TYPE_LINEAR:
		break;
	case LIBCOLOUR_ENCODING_TYPE_SIMPLE:
	case LIBCOLOUR_ENCODING_TYPE_REGULAR:
		if (colour->R < 0)  r_sign = -1, colour->R = -colour->R;
		if (colour->G < 0)  g_sign = -1, colour->G = -colour->G;
		if (colour->B < 0)  b_sign = -1, colour->B = -colour->B;
		if (space->encoding_type == LIBCOLOUR_ENCODING_TYPE_SIMPLE) {
			colour->R = xpow(colour->R, 1 / space->GAMMA);
			colour->G = xpow(colour->G, 1 / space->GAMMA);
			colour->B = xpow(colour->B, 1 / space->GAMMA);
		} else {
			colour->R = REGULAR(space, colour->R);
			colour->G = REGULAR(space, colour->G);
			colour->B = REGULAR(space, colour->B);
		}
		colour->R *= r_sign;
		colour->G *= g_sign;
		colour->B *= b_sign;
		break;
	case LIBCOLOUR_ENCODING_TYPE_CUSTOM:
		colour->R = (space->TO_ENCODED_RED)(colour->R);
		colour->G = (space->TO_ENCODED_GREEN)(colour->G);
		colour->B = (space->TO_ENCODED_BLUE)(colour->B);
		break;
	default:
		fprintf(stderr, "libcolour: invalid encoding type\n");
		abort();
	}
}

static void
rgb_decode(libcolour_rgb_t *restrict colour, const libcolour_rgb_t *restrict space)
{
	TYPE r_sign = 1, g_sign = 1, b_sign = 1;
	switch (space->encoding_type) {
	case LIBCOLOUR_ENCODING_TYPE_LINEAR:
		break;
	case LIBCOLOUR_ENCODING_TYPE_SIMPLE:
	case LIBCOLOUR_ENCODING_TYPE_REGULAR:
		if (colour->R < 0)  r_sign = -1, colour->R = -colour->R;
		if (colour->G < 0)  g_sign = -1, colour->G = -colour->G;
		if (colour->B < 0)  b_sign = -1, colour->B = -colour->B;
		if (space->encoding_type == LIBCOLOUR_ENCODING_TYPE_SIMPLE) {
			colour->R = xpow(colour->R, space->GAMMA);
			colour->G = xpow(colour->G, space->GAMMA);
			colour->B = xpow(colour->B, space->GAMMA);
		} else {
			colour->R = INVREGULAR(space, colour->R);
			colour->G = INVREGULAR(space, colour->G);
			colour->B = INVREGULAR(space, colour->B);
		}
		colour->R *= r_sign;
		colour->G *= g_sign;
		colour->B *= b_sign;
		break;
	case LIBCOLOUR_ENCODING_TYPE_CUSTOM:
		colour->R = (space->TO_DECODED_RED)(colour->R);
		colour->G = (space->TO_DECODED_GREEN)(colour->G);
		colour->B = (space->TO_DECODED_BLUE)(colour->B);
		break;
	default:
		fprintf(stderr, "libcolour: invalid encoding type\n");
		abort();
	}
}

static int
rgb_same_transfer(const libcolour_rgb_t *restrict a, const libcolour_rgb_t *restrict b)
{
	if (a->encoding_type != b->encoding_type)
		return 0;
	switch (a->encoding_type) {
	case LIBCOLOUR_ENCODING_TYPE_SIMPLE:
		return a->GAMMA == b->GAMMA;
	case LIBCOLOUR_ENCODING_TYPE_REGULAR:
		return a->GAMMA      == b->GAMMA  &&
		       a->OFFSET     == b->OFFSET &&
		       a->SLOPE      == b->SLOPE  &&
		       a->TRANSITION == b->TRANSITION;
	case LIBCOLOUR_ENCODING_TYPE_CUSTOM:
		return a->TO_ENCODED_RED   == b->TO_ENCODED_RED   &&
		       a->TO_ENCODED_GREEN == b->TO_ENCODED_GREEN &&
		       a->TO_ENCODED_BLUE  == b->TO_ENCODED_BLUE  &&
		       a->TO_DECODED_RED   == b->TO_DECODED_RED   &&
		       a->TO_DECODED_GREEN == b->TO_DECODED_GREEN &&
		       a->TO_DECODED_BLUE  == b->TO_DECODED_BLUE;
	default:
		return 1;
	}
}

static void
to_rgb(const libcolour_colour_t *restrict from, libcolour_rgb_t *restrict to)
{
	int have_transfer = 0, with_transfer = to->with_transfer;
	libcolour_ciexyz_t tmp;
	switch (from->model) {
	case LIBCOLOUR_CIEXYZ:
		ciexyz_to_rgb(&from->ciexyz, to);
		break;
	case LIBCOLOUR_RGB:
		if (!memcmp(from->rgb.M, to->M, sizeof(TYPE[3][3]))) {
			have_transfer = from->rgb.with_transfer;
			to->R = from->rgb.R;
			to->G = from->rgb.G;
			to->B = from->rgb.B;
			if (have_transfer && with_transfer && !rgb_same_transfer(&from->rgb, to))
				rgb_decode(to, &from->rgb), have_transfer = 0;
			break;
		}
		/* fall through */
	default:
		tmp.model = LIBCOLOUR_CIEXYZ;
		to_ciexyz(from, &tmp);
		ciexyz_to_rgb(&tmp, to);
		break;
	}

	if (have_transfer != with_transfer) {
		if (with_transfer)
			rgb_encode(to, to);
		else
			rgb_decode(to, &from->rgb);
	}
}


static void
ciexyz_to_srgb(const libcolour_ciexyz_t *restrict from, libcolour_srgb_t *restrict to)
{
	TRANSFORM(to->R, to->G, to->B, from->X, from->Y, from->Z,
		   3.240446254647737500675930277794, -1.537134761820080575134284117667, -0.498530193022728718155178739835,
		  -0.969266606244679751469561779231,  1.876011959788370209167851498933,  0.041556042214430065351304932619,
		   0.055643503564352832235773149705, -0.204026179735960239147729566866,  1.057226567722703292062647051353);
}

static inline TYPE
srgb_encode(TYPE t)
{
	TYPE sign = 1;
	if (t < 0) {
		t = -t;
		sign = -1;
	}
	t = t <= D(0.0031306684425217108) ? D(12.92) * t
		: D(1.055) * xpow(t, 1 / D(2.4)) - D(0.055);
	return t * sign;
}

static inline TYPE
srgb_decode(TYPE t)
{
	TYPE sign = 1;
	if (t < 0) {
		t = -t;
		sign = -1;
	}
	t = t <= D(0.0031306684425217108) * D(12.92) ? t / D(12.92)
		: xpow((t + D(0.055)) / D(1.055), D(2.4));
	return t * sign;
}

static void
srgb_to_srgb(const libcolour_srgb_t *restrict from, libcolour_srgb_t *restrict to)
{
	if (from->with_transfer == to->with_transfer) {
		*to = *from;
	} else if (to->with_transfer) {
		to->R = srgb_encode(from->R);
		to->G = srgb_encode(from->G);
		to->B = srgb_encode(from->B);
	} else {
		to->R = srgb_decode(from->R);
		to->G = srgb_decode(from->G);
		to->B = srgb_decode(from->B);
	}
}

static void
yiq_to_srgb(const libcolour_yiq_t *restrict from, libcolour_srgb_t *restrict to)
{
	TRANSFORM(to->R, to->G, to->B, from->Y, from->I, from->Q,
		  1,  0.95629483232089407263032398986979387700557708740234,  0.62102512544472865396727456754888407886028289794922,
		  1, -0.27212147408397735492968649850809015333652496337891, -0.64738095351761570928061928498209454119205474853516,
		  1, -1.10698990856712820018969978264067322015762329101562,  1.70461497549882934343656870623817667365074157714844);
	/* ⎛1    1000 cos 33° / 877                                  1000 sin 33° / 877                               ⎞
	   ⎜1    9500 sin 33° / 24067 - 299000 * cos 33° / 514799    -9500 cos 33° / 24067 - 299000 * sin 33° / 514799⎟
	   ⎝1    -250 sin 33° / 123                                  250 cos 33° / 123                                ⎠
	*/
}

static void
ydbdr_to_srgb(const libcolour_ydbdr_t *restrict from, libcolour_srgb_t *restrict to)
{
	TRANSFORM(to->R, to->G, to->B, from->Y, from->Db, from->Dr,
		  1,  0.000092303716148, -0.525912630661865,
		  1, -0.129132898890509,  0.267899328207599,
		  1,  0.664679059978955, -0.000079202543533);
}

static void
ypbpr_to_srgb(const libcolour_ypbpr_t *restrict from, libcolour_srgb_t *restrict to)
{
	TYPE Y = from->Y, Pb = from->Pb, Pr = from->Pr;
	to->R = Pr + Y;
	to->B = Pb + Y;
	to->G = (Y - to->R * D(0.2126) - to->B * D(0.0722)) / D(0.7152);
}

static void
yuv_to_srgb(const libcolour_yuv_t *restrict from, libcolour_srgb_t *restrict to)
{
	TRANSFORM(to->R, to->G, to->B, from->Y, from->U, from->V,
		  1,  0.00028328010485821202317155420580263580632163211703,  1.14070449590558520291949662350816652178764343261719,
		  1, -0.39630886669497211727275498560629785060882568359375, -0.58107364288228224857846271333983168005943298339844,
		  1,  2.03990003507541306504435851820744574069976806640625,  0.00017179031692307700847528739718228507626918144524);
}

static void
ycgco_to_srgb(const libcolour_ycgco_t *restrict from, libcolour_srgb_t *restrict to)
{
	TYPE Y = from->Y, Cg = from->Cg, Co = from->Co;
	to->R = Y - Cg + Co;
	to->G = Y + Cg;
	to->B = Y - Cg - Co;
}

static void
other_to_srgb(const libcolour_colour_t *restrict from, libcolour_srgb_t *restrict to)
{
	libcolour_ciexyz_t tmp;
	tmp.model = LIBCOLOUR_CIEXYZ;
	to_ciexyz(from, &tmp);
	ciexyz_to_srgb(&tmp, to);
}

static void
to_srgb(const libcolour_colour_t *restrict from, libcolour_srgb_t *restrict to)
{
	libcolour_srgb_t tmp;
	switch (from->model) {
	case LIBCOLOUR_CIEXYZ:
		ciexyz_to_srgb(&from->ciexyz, to);
		break;
	case LIBCOLOUR_SRGB:
		srgb_to_srgb(&from->srgb, to);
		return;
	case LIBCOLOUR_YIQ:
		yiq_to_srgb(&from->yiq, to);
		break;
	case LIBCOLOUR_YDBDR:
		ydbdr_to_srgb(&from->ydbdr, to);
		break;
	case LIBCOLOUR_YPBPR:
		ypbpr_to_srgb(&from->ypbpr, to);
		break;
	case LIBCOLOUR_YUV:
		yuv_to_srgb(&from->yuv, to);
		break;
	case LIBCOLOUR_YCGCO:
		ycgco_to_srgb(&from->ycgco, to);
		break;
	default:
		other_to_srgb(from, to);
		break;
	}
	if (to->with_transfer) {
		tmp = *to;
		tmp.with_transfer = 0;
		srgb_to_srgb(&tmp, to);
	}
}


static void
ciexyz_to_ciexyy(const libcolour_ciexyz_t *restrict from, libcolour_ciexyy_t *restrict to)
{
	TYPE X = from->X, Y = from->Y, Z = from->Z;
	TYPE s = X + Y + Z;
	to->x = X / s;
	to->y = Y / s;
	to->Y = Y;
	if (WASDIV0(to->x) || WASDIV0(to->y))
		to->x = to->y = 0;
}

static void
other_to_ciexyy(const libcolour_colour_t *restrict from, libcolour_ciexyy_t *restrict to)
{
	libcolour_ciexyz_t tmp;
	tmp.model = LIBCOLOUR_CIEXYZ;
	to_ciexyz(from, &tmp);
	ciexyz_to_ciexyy(&tmp, to);
}

static void
srgb_to_ciexyy(const libcolour_srgb_t *restrict from, libcolour_ciexyy_t *restrict to)
{
	libcolour_srgb_t tmp;
	tmp.model = LIBCOLOUR_SRGB;
	if (from->with_transfer) {
		tmp.with_transfer = 0;
		to_srgb((const libcolour_colour_t*)from, &tmp);
	} else {
		tmp = *from;
	}
	if (tmp.R == 0 && tmp.G == 0 && tmp.B == 0) {
		to->x = D(0.31272660439158);
		to->y = D(0.32902315240275);
		to->Y = 0;
	} else {
		other_to_ciexyy((const libcolour_colour_t*)&tmp, to);
	}
}

static void
to_ciexyy(const libcolour_colour_t *restrict from, libcolour_ciexyy_t *restrict to)
{
	switch (from->model) {
	case LIBCOLOUR_CIEXYY:
		*to = from->ciexyy;
		return;
	case LIBCOLOUR_CIEXYZ:
		ciexyz_to_ciexyy(&from->ciexyz, to);
		return;
	case LIBCOLOUR_SRGB:
		srgb_to_ciexyy(&from->srgb, to);
		return;
	default:
		other_to_ciexyy(from, to);
		return;
	}
}


static void
rgb_to_ciexyz(const libcolour_rgb_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	libcolour_rgb_t tmp;
	TYPE R, G, B;
	if (from->with_transfer) {
		tmp = *from;
		tmp.with_transfer = 0;
		to_rgb((const libcolour_colour_t *)from, &tmp);
		R = tmp.R, G = tmp.G, B = tmp.B;
	} else {
		R = from->R, G = from->G, B = from->B;
	}
	to->X = from->M[0][0] * R + from->M[0][1] * G + from->M[0][2] * B;
	to->Y = from->M[1][0] * R + from->M[1][1] * G + from->M[1][2] * B;
	to->Z = from->M[2][0] * R + from->M[2][1] * G + from->M[2][2] * B;
}

static void srgb_to_ciexyz(const libcolour_srgb_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	libcolour_srgb_t tmp;
	TYPE R, G, B;
	if (from->with_transfer) {
		tmp.model = LIBCOLOUR_SRGB;
		tmp.with_transfer = 0;
		to_srgb((const libcolour_colour_t*)from, &tmp);
		R = tmp.R, G = tmp.G, B = tmp.B;
	} else {
		R = from->R, G = from->G, B = from->B;
	}
	TRANSFORM(to->X, to->Y, to->Z, R, G, B,
		  0.412457445582367576708548995157, 0.357575865245515878143578447634, 0.180437247826399665973085006954,
		  0.212673370378408277403536885686, 0.715151730491031756287156895269, 0.072174899130559869164791564344,
		  0.019333942761673460208893260415, 0.119191955081838593666354597644, 0.950302838552371742508739771438);
}

static void
ciexyy_to_ciexyz(const libcolour_ciexyy_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TYPE x = from->x, y = from->y, Y = from->Y;
	TYPE Yy = Y / y;
	if (WASDIV0(Yy)) {
		to->X = to->Y = to->Z = Y;
	} else {
		to->X = x * Yy;
		to->Y = Y;
		to->Z = (1 - x - y) * Yy;
	}
}

static inline TYPE
cielab_finv(TYPE t)
{
	return (t > D(6.) / D(29.)) ? t * t * t : (t - D(4.) / D(29.)) * 108 / 841;
}

static void
cielab_to_ciexyz(const libcolour_cielab_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TYPE L = from->L, a = from->a, b = from->b;
	to->Y = (L + 16) / 116;
	to->X = to->Y + a / 500;
	to->Z = to->Y - b / 200;
	to->X = cielab_finv(to->X) * D(0.95047);
	to->Y = cielab_finv(to->Y);
	to->Z = cielab_finv(to->Z) * D(1.08883);
}

static void
cieluv_to_ciexyz(const libcolour_cieluv_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TYPE X = from->white.X, Y = from->white.Y, L = from->L, L13 = from->L * 13;
	TYPE t = X + 15 * Y + 3 * from->white.Z;
	TYPE u = from->u / L13 + 4 * X / t;
	TYPE v = from->v / L13 + 9 * Y / t;
	if (L <= 8) {
		Y *= L * 27 / 24389;
	} else {
		L = (L + 16) / 116;
		Y *= L * L * L;
	}
	to->X = D(2.25) * Y * u / v;
	to->Y = Y;
	to->Z = Y * (3 / v - D(0.75) * u / v - 5);
}

static void
cielchuv_to_ciexyz(const libcolour_cielchuv_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	libcolour_cieluv_t tmp;
	tmp.model = LIBCOLOUR_CIELUV;
	tmp.white = from->white;
	to_cieluv((const libcolour_colour_t*)from, &tmp);
	cieluv_to_ciexyz(&tmp, to);
}

static void
yiq_to_ciexyz(const libcolour_yiq_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TRANSFORM(to->X, to->Y, to->Z, from->Y, from->I, from->Q,
		   0.95047055865428309306963683411595411598682403564453,
		   0.09738463974178063198294807989441324025392532348633,
		   0.33223466706854809515903070860076695680618286132812,
		   0.99999999999999988897769753748434595763683319091797,
		  -0.07112658301916767455974621725545148365199565887451,
		  -0.20786968876398304040264974901219829916954040527344,
		   1.08882873639588373393394249433185905218124389648438,
		  -1.06592139332461721679123911599162966012954711914062,
		   1.55474471255181900808395312196807935833930969238281);
}

static void
ydbdr_to_ciexyz(const libcolour_ydbdr_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TRANSFORM(to->X, to->Y, to->Z, from->Y, from->Db, from->Dr,
		   0.95047055865428309306963683411595411598682403564453,
		   0.07379612357298576119646327242662664502859115600586,
		  -0.12113653724874726136384595065464964136481285095215,
		   0.99999999999999988897769753748434595763683319091797,
		  -0.04435684145428285540813106990754022262990474700928,
		   0.07973534004202506575431641522300196811556816101074,
		   1.08882873639588373393394249433185905218124389648438,
		   0.61625657933494271123464613992837257683277130126953,
		   0.02168821359337728266192257819966471288353204727173);
}

static void
yuv_to_ciexyz(const libcolour_yuv_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TRANSFORM(to->X, to->Y, to->Z, from->Y, from->U, from->V,
		   0.95047055865428309306963683411595411598682403564453,
		   0.22648030324549334180161963558930438011884689331055,
		   0.26274514929253273143316960158699657768011093139648,
		   0.99999999999999988897769753748434595763683319091797,
		  -0.13613114642319409930415474718756740912795066833496,
		  -0.17294595255115238763288232348713790997862815856934,
		   1.08882873639588373393394249433185905218124389648438,
		   1.89129144197893928058817891724174842238426208496094,
		  -0.04704173528403532422714761196402832865715026855469);
}

static void
ypbpr_to_ciexyz(const libcolour_ypbpr_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TRANSFORM(to->X, to->Y, to->Z, from->Y, from->Pb, from->Pr,
		   0.95047055865428298204733437160030007362365722656250,
		   0.14433968424876231217979238863335922360420227050781,
		   0.30616461986760712399302519770571961998939514160156,
		   0.99999999999999977795539507496869191527366638183594,
		  -0.00002022802471486617736928792510298080742359161377,
		   0.00008771894888734421691367515450110659003257751465,
		   1.08882873639588373393394249433185905218124389648438,
		   0.93827031735982591165168287261622026562690734863281,
		  -0.01609699914324668607035206946420657914131879806519);
}

static void
ycgco_to_ciexyz(const libcolour_ycgco_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TRANSFORM(to->X, to->Y, to->Z, from->Y, from->Cg, from->Co,
		   0.95047055865428309306963683411595411598682403564453,
		  -0.23531882816325136453805555447615915909409523010254,
		   0.23202019775596791073546398820326430723071098327637,
		   0.99999999999999988897769753748434595763683319091797,
		   0.43030346098206362359661625305307097733020782470703,
		   0.14049847124784842211653312915586866438388824462891,
		   1.08882873639588373393394249433185905218124389648438,
		  -0.85044482623220662986796014592982828617095947265625,
		  -0.93096889579069830311652822274481877684593200683594);
}

static void
cie1960ucs_to_ciexyz(const libcolour_cie1960ucs_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	TYPE u = from->u, v = from->v, Y = from->Y;
	to->X = D(1.5) * Y * u / v;
	to->Y = Y;
	to->Z = (4 * Y - Y * u - 10 * Y * v) / (2 * v);
}

static void
cieuvw_to_ciexyz(const libcolour_cieuvw_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	libcolour_cie1960ucs_t tmp;
	tmp.model = LIBCOLOUR_CIE1960UCS;
	to_cie1960ucs((const libcolour_colour_t *)from, &tmp);
	cie1960ucs_to_ciexyz(&tmp, to);
}

static void
other_to_ciexyz(const libcolour_colour_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	libcolour_srgb_t tmp;
	tmp.model = LIBCOLOUR_SRGB;
	tmp.with_transfer = 0;
	to_srgb(from, &tmp);
	srgb_to_ciexyz(&tmp, to);
}

static void to_ciexyz(const libcolour_colour_t *restrict from, libcolour_ciexyz_t *restrict to)
{
	switch (from->model) {
	case LIBCOLOUR_RGB:
		rgb_to_ciexyz(&from->rgb, to);
		break;
	case LIBCOLOUR_SRGB:
		srgb_to_ciexyz(&from->srgb, to);
		break;
	case LIBCOLOUR_CIEXYY:
		ciexyy_to_ciexyz(&from->ciexyy, to);
		break;
	case LIBCOLOUR_CIEXYZ:
		*to = from->ciexyz;
		break;
	case LIBCOLOUR_CIELAB:
		cielab_to_ciexyz(&from->cielab, to);
		break;
	case LIBCOLOUR_CIELUV:
		cieluv_to_ciexyz(&from->cieluv, to);
		break;
	case LIBCOLOUR_CIELCHUV:
		cielchuv_to_ciexyz(&from->cielchuv, to);
		break;
	case LIBCOLOUR_YIQ:
		yiq_to_ciexyz(&from->yiq, to);
		break;
	case LIBCOLOUR_YDBDR:
		ydbdr_to_ciexyz(&from->ydbdr, to);
		break;
	case LIBCOLOUR_YUV:
		yuv_to_ciexyz(&from->yuv, to);
		break;
	case LIBCOLOUR_YPBPR:
		ypbpr_to_ciexyz(&from->ypbpr, to);
		break;
	case LIBCOLOUR_YCGCO:
		ycgco_to_ciexyz(&from->ycgco, to);
		break;
	case LIBCOLOUR_CIE1960UCS:
		cie1960ucs_to_ciexyz(&from->cie1960ucs, to);
		break;
	case LIBCOLOUR_CIEUVW:
		cieuvw_to_ciexyz(&from->cieuvw, to);
		break;
	default:
		other_to_ciexyz(from, to);
		break;
	}
}


static inline TYPE
cielab_f(TYPE t)
{
	return (t > D(216.) / D(24389.)) ? xcbrt(t) : t * D(841.) / D(108.) + D(4.) / D(29.);
}

static void
ciexyz_to_cielab(const libcolour_ciexyz_t *restrict from, libcolour_cielab_t *restrict to)
{
	TYPE X = from->X, Y = from->Y, Z = from->Z;
	X /= D(0.95047);
	Z /= D(1.08883);
	Y = cielab_f(Y);
	to->L = 116 * Y - 16;
	to->a = 500 * (cielab_f(X) - Y);
	to->b = 200 * (Y - cielab_f(Z));
}

static void
other_to_cielab(const libcolour_colour_t *restrict from, libcolour_cielab_t *restrict to)
{
	libcolour_ciexyz_t tmp;
	tmp.model = LIBCOLOUR_CIEXYZ;
	to_ciexyz(from, &tmp);
	ciexyz_to_cielab(&tmp, to);
}

static void
to_cielab(const libcolour_colour_t *restrict from, libcolour_cielab_t *restrict to)
{
	switch (from->model) {
	case LIBCOLOUR_CIEXYZ:
		ciexyz_to_cielab(&from->ciexyz, to);
		return;
	case LIBCOLOUR_CIELAB:
		*to = from->cielab;
		return;
	default:
		other_to_cielab(from, to);
		return;
	}
}


static void
ciexyz_to_cieluv(const libcolour_ciexyz_t *restrict from, libcolour_cieluv_t *restrict to)
{
	TYPE t, u, v, y, y2;
	t = to->white.X + 15 * to->white.Y + 3 * to->white.Z;
	u = 4 * to->white.X / t;
	v = 9 * to->white.Y / t;
	t = from->X + 15 * from->Y + 3 * from->Z;
	u = 4 * from->X / t - u;
	v = 9 * from->Y / t - v;
	y = from->Y / to->white.Y;
	y2 = y * 24389;
	y = y2 <= 216 ? y2 / 27 : xcbrt(y) * 116 - 16;
	to->L = y;
	y *= 13;
	to->u = u * y;
	to->v = v * y;
}

static void
cielchuv_to_cieluv(const libcolour_cielchuv_t *restrict from, libcolour_cieluv_t *restrict to)
{
	libcolour_ciexyz_t tmp;
	libcolour_cielchuv_t tmp2;
	TYPE L, C, h;
	if (to->white.X != from->white.X || to->white.Y != from->white.Y || to->white.Z != from->white.Z) {
		tmp.model = LIBCOLOUR_CIEXYZ;
		tmp2.model = LIBCOLOUR_CIELCHUV;
		tmp2.white = to->white;
		tmp2.one_revolution = PI2;
		to_ciexyz((const libcolour_colour_t*)from, &tmp);
		to_cielchuv((const libcolour_colour_t*)&tmp, &tmp2);
		L = tmp2.L, C = tmp2.C, h = tmp2.h;
	} else {
		L = from->L, C = from->C, h = from->h * PI2 / from->one_revolution;
	}
	to->L = L;
	to->u = C * xcos(h);
	to->v = C * xsin(h);
}

static void
other_to_cieluv(const libcolour_colour_t *restrict from, libcolour_cieluv_t *restrict to)
{
	libcolour_ciexyz_t tmp;
	tmp.model = LIBCOLOUR_CIEXYZ;
	to_ciexyz(from, &tmp);
	ciexyz_to_cieluv(&tmp, to);
}

static void
to_cieluv(const libcolour_colour_t *restrict from, libcolour_cieluv_t *restrict to)
{
	switch (from->model) {
	case LIBCOLOUR_CIEXYZ:
		ciexyz_to_cieluv(&from->ciexyz, to);
		break;
	case LIBCOLOUR_CIELCHUV:
		cielchuv_to_cieluv(&from->cielchuv, to);
		break;
	case LIBCOLOUR_CIELUV:
		if (to->white.X == from->cieluv.white.X &&
		    to->white.Y == from->cieluv.white.Y &&
		    to->white.Z == from->cieluv.white.Z) {
			*to = from->cieluv;
			break;
		}
		/* fall through */
	default:
		other_to_cieluv(from, to);
		break;
	}
}


static void
cieluv_to_cielchuv(const libcolour_cieluv_t *restrict from, libcolour_cielchuv_t *restrict to)
{
	libcolour_cieluv_t tmp;
	TYPE L, u, v;
	if (to->white.X != from->white.X || to->white.Y != from->white.Y || to->white.Z != from->white.Z) {
		tmp.model = LIBCOLOUR_CIELUV;
		tmp.white = to->white;
		to_cieluv((const libcolour_colour_t *)from, &tmp);
		L = tmp.L, u = tmp.u, v = tmp.v;
	} else {
		L = from->L, u = from->u, v = from->v;
	}
	to->L = L;
	to->C = xsqrt(u * u + v * v);
	to->h = xatan2(v, u) / PI2 * to->one_revolution;
	if (!WASDIV0(to->h) && (to->h < 0))
		to->h += to->one_revolution;
}

static void
other_to_cielchuv(const libcolour_colour_t *restrict from, libcolour_cielchuv_t *restrict to)
{
	libcolour_cieluv_t tmp;
	tmp.model = LIBCOLOUR_CIELUV;
	tmp.white = to->white;
	to_cieluv(from, &tmp);
	cieluv_to_cielchuv(&tmp, to);
}

static void
to_cielchuv(const libcolour_colour_t *restrict from, libcolour_cielchuv_t *restrict to)
{
	TYPE one_revolution;
	switch (from->model) {
	case LIBCOLOUR_CIELUV:
		cieluv_to_cielchuv(&from->cieluv, to);
		break;
	case LIBCOLOUR_CIELCHUV:
		if (to->white.X == from->cielchuv.white.X &&
		    to->white.Y == from->cielchuv.white.Y &&
		    to->white.Z == from->cielchuv.white.Z) {
			if (to->one_revolution == from->cielchuv.one_revolution) {
				*to = from->cielchuv;
			} else {
				one_revolution = to->one_revolution;
				*to = from->cielchuv;
				to->one_revolution = one_revolution;
				to->h = to->h / from->cielchuv.one_revolution * one_revolution;
			}
			break;
		}
		/* fall through */
	default:
		other_to_cielchuv(from, to);
		break;
	}
}


static void
to_yiq(const libcolour_colour_t *restrict from, libcolour_yiq_t *restrict to)
{
	libcolour_colour_t tmp = *from;
	switch (from->model) {
	case LIBCOLOUR_YIQ:
		*to = from->yiq;
		break;
	case LIBCOLOUR_SRGB:
		if (tmp.srgb.with_transfer) {
			tmp.srgb.with_transfer = 0;
			to_srgb(from, &tmp.srgb);
		}
		TRANSFORM(to->Y, to->I, to->Q, tmp.srgb.R, tmp.srgb.G, tmp.srgb.B, 0.299, 0.587, 0.114,
			   0.59571613491277464191853141528554260730743408203125,  /* (0.877 cos 33°)(1 - 0.299) - (0.492 sin 33°)(-0.299) */
			  -0.27445283783925644716106262421817518770694732666016,  /* (0.877 cos 33°)(-0.587)    - (0.492 sin 33°)(-0.587) */
			  -0.32126329707351808373516632855171337723731994628906,  /* (0.877 cos 33°)(-0.114)    - (0.492 sin 33°)(1 - 0.114) */
			   0.21145640212011795888713550084503367543220520019531,  /* (0.877 sin 33°)(1 - 0.299) + (0.492 cos 33°)(-0.299) */
			  -0.52259104529161115593183239980135113000869750976562,  /* (0.877 sin 33°)(-0.587)    + (0.492 cos 33°)(-0.587) */
			   0.31113464317149330806699936147197149693965911865234); /* (0.877 sin 33°)(-0.114)    + (0.492 cos 33°)(1 - 0.114) */
		break;
	default:
		tmp.model = LIBCOLOUR_CIEXYZ;
		to_ciexyz(from, &tmp.ciexyz);
		/* fall through */
	case LIBCOLOUR_CIEXYZ:
		TRANSFORM(to->Y, to->I, to->Q, tmp.ciexyz.X, tmp.ciexyz.Y, tmp.ciexyz.Z,
			   0.40627729168038273499519164033699780702590942382812,
			   0.61835674212166968910509012857801280915737152099609,
			  -0.00414330221353725880462093300593551248311996459961,
			   2.17852787350219845308174626552499830722808837890625,
			  -1.36502666214454104753883711964590474963188171386719,
			  -0.64803574634025240541745915834326297044754028320312,
			   1.20905577682138853923277110880007967352867126464844,
			  -1.36890364998339797431015085749095305800437927246094,
			   0.20180559439597040016778350945969577878713607788086);
		break;
	}
}


static void
to_ydbdr(const libcolour_colour_t *restrict from, libcolour_ydbdr_t *restrict to)
{
	libcolour_colour_t tmp = *from;
	switch (from->model) {
	case LIBCOLOUR_YDBDR:
		*to = from->ydbdr;
		break;
	case LIBCOLOUR_SRGB:
		if (tmp.srgb.with_transfer) {
			tmp.srgb.with_transfer = 0;
			to_srgb(from, &tmp.srgb);
		}
		TRANSFORM(to->Y, to->Db, to->Dr, tmp.srgb.R, tmp.srgb.G, tmp.srgb.B,
			   0.299,  0.587, 0.114,
			  -0.450, -0.883, 1.333,
			  -1.333,  1.116, 0.217);
		break;
	case LIBCOLOUR_YUV:
		to->Y  =  tmp.yuv.Y;
		to->Db =  tmp.yuv.U * D(3.069);
		to->Dr = -tmp.yuv.V * D(2.169);
		break;
	default:
		tmp.model = LIBCOLOUR_CIEXYZ;
		to_ciexyz(from, &tmp.ciexyz);
		/* fall through */
	case LIBCOLOUR_CIEXYZ:
		TRANSFORM(to->Y, to->Db, to->Dr, tmp.ciexyz.X, tmp.ciexyz.Y, tmp.ciexyz.Z,
			   0.40627729168038273499519164033699780702590942382812,
			   0.61835674212166968910509012857801280915737152099609,
			  -0.00414330221353725880462093300593551248311996459961,
			  -0.52816561102614745237815441214479506015777587890625,
			  -1.23677481526212962315014465275453403592109680175781,
			   1.59692761635924940222253098909277468919754028320312,
			  -5.38914174974103143966885909321717917919158935546875,
			   4.09835630362728497999569299281574785709381103515625,
			   0.94033545560642795013706063400604762136936187744141);
		break;
	}
}


static void
to_yuv(const libcolour_colour_t *restrict from, libcolour_yuv_t *restrict to)
{
	libcolour_colour_t tmp = *from;
	switch (from->model) {
	case LIBCOLOUR_YUV:
		*to = from->yuv;
		break;
	case LIBCOLOUR_YDBDR:
		to->Y = from->ydbdr.Y;
		to->U = from->ydbdr.Db /  D(3.069);
		to->V = from->ydbdr.Dr / D(-2.169);
		break;
	case LIBCOLOUR_SRGB:
		if (tmp.srgb.with_transfer) {
			tmp.srgb.with_transfer = 0;
			to_srgb(from, &tmp.srgb);
		}
		TRANSFORM(to->Y, to->U, to->V, tmp.srgb.R, tmp.srgb.G, tmp.srgb.B,
			   0.29899999999999998800959133404830936342477798461914,
			   0.58699999999999996624922005139524117112159729003906,
			   0.11400000000000000410782519111307919956743717193604,
			  -0.14662756598240470062854967636667424812912940979004,
			  -0.28771586836102963635752871596196200698614120483398,
			   0.43434343434343436474165400795754976570606231689453,
			   0.61456892577224520035628074765554629266262054443359,
			  -0.51452282157676354490405401520547457039356231689453,
			  -0.10004610419548178035231700278018251992762088775635);
		break;
	default:
		tmp.model = LIBCOLOUR_CIEXYZ;
		to_ciexyz(from, &tmp.ciexyz);
		/* fall through */
	case LIBCOLOUR_CIEXYZ:
		TRANSFORM(to->Y, to->U, to->V, tmp.ciexyz.X, tmp.ciexyz.Y, tmp.ciexyz.Z,
			   0.40627729168038273499519164033699780702590942382812,
			   0.61835674212166968910509012857801280915737152099609,
			  -0.00414330221353725880462093300593551248311996459961,
			  -0.17209697328971895746718701047939248383045196533203,
			  -0.40298951295605395239718404809536878019571304321289,
			   0.52034135430408912093014350830344483256340026855469,
			   2.48462044709130047692724474472925066947937011718750,
			  -1.88951420176453876997868519538315013051033020019531,
			  -0.43353409663735725798616726933687459677457809448242);
		break;
	}
}


static void
to_ypbpr(const libcolour_colour_t *restrict from, libcolour_ypbpr_t *restrict to)
{
	libcolour_colour_t tmp = *from;
	switch (from->model) {
	case LIBCOLOUR_YPBPR:
		*to = from->ypbpr;
		break;
	case LIBCOLOUR_SRGB:
		if (tmp.srgb.with_transfer) {
			tmp.srgb.with_transfer = 0;
			to_srgb(from, &tmp.srgb);
		}
		to->Y  = tmp.srgb.R * D(0.2126) +
			 tmp.srgb.G * D(0.7152) +
			 tmp.srgb.B * D(0.0722);
		to->Pb = tmp.srgb.B - to->Y;
		to->Pr = tmp.srgb.R - to->Y;
		break;
	default:
		tmp.model = LIBCOLOUR_CIEXYZ;
		to_ciexyz(from, &tmp.ciexyz);
		/* fall through */
	case LIBCOLOUR_CIEXYZ:
		TRANSFORM(to->Y, to->Pb, to->Pr, tmp.ciexyz.X, tmp.ciexyz.Y, tmp.ciexyz.Z,
			  -0.00028314209073960778378920011277841695118695497513,
			   1.00019821310075673892470149439759552478790283203125,
			   0.00006512054470741990286342115723527967929840087891,
			   0.05592664565509243568275365987574332393705844879150,
			  -1.20422439283671711685030913940863683819770812988281,
			   1.05716144717799576113748116767965257167816162109375,
			   3.24072939673847715269516811531502753496170043945312,
			  -2.53733297492083753610359053709544241428375244140625,
			  -0.49859531356743613805804216099204495549201965332031);
		break;
	}
}


static void
to_ycgco(const libcolour_colour_t *restrict from, libcolour_ycgco_t *restrict to)
{
	libcolour_colour_t tmp = *from;
	switch (from->model) {
	case LIBCOLOUR_YCGCO:
		*to = from->ycgco;
		break;
	case LIBCOLOUR_SRGB:
		if (tmp.srgb.with_transfer) {
			tmp.srgb.with_transfer = 0;
			to_srgb(from, &tmp.srgb);
		}
		to->Y  =  tmp.srgb.R / 4 + tmp.srgb.G / 2 + tmp.srgb.B / 4;
		to->Cg = -tmp.srgb.R / 4 + tmp.srgb.G / 2 - tmp.srgb.B / 4;
		to->Co =  tmp.srgb.R / 2 - tmp.srgb.B / 2;
		break;
	default:
		tmp.model = LIBCOLOUR_CIEXYZ;
		to_ciexyz(from, &tmp.ciexyz);
		/* fall through */
	case LIBCOLOUR_CIEXYZ:
		TRANSFORM(to->Y, to->Cg, to->Co, tmp.ciexyz.X, tmp.ciexyz.Y, tmp.ciexyz.Z,
			   0.33938913643068269188063368346774950623512268066406,
			   0.50271574450517486631895280879689380526542663574219,
			   0.16045211478220866574417868832824751734733581542969,
			  -1.30865574267536244335019546269904822111129760742188,
			   1.37329621528319534284889869013568386435508728027344,
			  -0.11889607256777862120955546743061859160661697387695,
			   1.59240137554169236544510113162687048316001892089844,
			  -0.66655429104206020962664069884340278804302215576172,
			  -0.77787838037271606062006412685150280594825744628906);
		break;
	}
}


static void
to_cie1960ucs(const libcolour_colour_t *restrict from, libcolour_cie1960ucs_t *restrict to)
{
	libcolour_colour_t tmp = *from;
	TYPE u, v, w, y;
	switch (from->model) {
	case LIBCOLOUR_CIE1960UCS:
		*to = from->cie1960ucs;
		return;
	case LIBCOLOUR_CIEUVW:
		u = from->cieuvw.U, v = from->cieuvw.V, w = from->cieuvw.W;
		y = (w + 17) / 25;
		y *= y * y;
		w *= 13;
		to->u = u / w + from->cieuvw.u0;
		to->v = v / w + from->cieuvw.v0;
		to->Y = y;
		return;
	default:
		tmp.model = LIBCOLOUR_CIEXYZ;
		to_ciexyz(from, &tmp.ciexyz);
		/* fall through */
	case LIBCOLOUR_CIEXYZ:
		w = tmp.ciexyz.X + 15 * tmp.ciexyz.Y + 3 * tmp.ciexyz.Z;
		to->u = 4 * tmp.ciexyz.X / w;
		to->v = 6 * tmp.ciexyz.Y / w;
		to->Y = tmp.ciexyz.Y;
		return;
	}
}


static void
to_cieuvw(const libcolour_colour_t *restrict from, libcolour_cieuvw_t *restrict to)
{
	TYPE U, V, W, w;
	libcolour_colour_t tmp = *from;
	switch (from->model) {
	case LIBCOLOUR_CIEUVW:
		U = from->cieuvw.U, V = from->cieuvw.V, W = from->cieuvw.W;
		w = W * 13;
		U += w * (from->cieuvw.u0 - to->u0);
		V += w * (from->cieuvw.v0 - to->v0);
		to->U = U, to->V = V, to->W = W;
		break;
	default:
		tmp.model = LIBCOLOUR_CIE1960UCS;
		to_cie1960ucs(from, &tmp.cie1960ucs);
		/* fall through */
	case LIBCOLOUR_CIE1960UCS:
		U = tmp.cie1960ucs.u, V = tmp.cie1960ucs.v, W = tmp.cie1960ucs.Y;
		W = 25 * xcbrt(W) - 17;
		w = W * 13;
		to->U = w * (U - to->u0);
		to->V = w * (V - to->v0);
		to->W = W;
		break;
	}
}



int
libcolour_convert(const libcolour_colour_t *restrict from, libcolour_colour_t *restrict to)
{
#define X(C, T, N) 1 +
	if (from->model < 0 || from->model > LIST_MODELS(X) 0) {
#undef X
		errno = EINVAL;
		return -1;
	}
	switch (to->model) {
	case LIBCOLOUR_RGB:
		to_rgb(from, &to->rgb);
		break;
	case LIBCOLOUR_SRGB:
		to_srgb(from, &to->srgb);
		break;
	case LIBCOLOUR_CIEXYY:
		to_ciexyy(from, &to->ciexyy);
		break;
	case LIBCOLOUR_CIEXYZ:
		to_ciexyz(from, &to->ciexyz);
		break;
	case LIBCOLOUR_CIELAB:
		to_cielab(from, &to->cielab);
		break;
	case LIBCOLOUR_CIELUV:
		to_cieluv(from, &to->cieluv);
		break;
	case LIBCOLOUR_CIELCHUV:
		to_cielchuv(from, &to->cielchuv);
		break;
	case LIBCOLOUR_YIQ:
		to_yiq(from, &to->yiq);
		break;
	case LIBCOLOUR_YDBDR:
		to_ydbdr(from, &to->ydbdr);
		break;
	case LIBCOLOUR_YUV:
		to_yuv(from, &to->yuv);
		break;
	case LIBCOLOUR_YPBPR:
		to_ypbpr(from, &to->ypbpr);
		break;
	case LIBCOLOUR_YCGCO:
		to_ycgco(from, &to->ycgco);
		break;
	case LIBCOLOUR_CIE1960UCS:
		to_cie1960ucs(from, &to->cie1960ucs);
		break;
	case LIBCOLOUR_CIEUVW:
		to_cieuvw(from, &to->cieuvw);
		break;
	default:
		errno = EINVAL;
		return -1;
	}
	return 0;
}